Skip to contentSkip to conversation

Introduce new mode validation callbacks

PATCH Superseded Jose Abreu 3 participants 16 messages May 4, 2017 – May 8, 2017

Subsystems (3)

v1 of 5 Superseded Latest is v5 →

lore
Share & tools
lore

Jose Abreu

author
#0 lore raw

cover Introduce new mode validation callbacks

This series is a follow up from the discussion at [1]. We start by introducing crtc->mode_valid(), encoder->mode_valid() and bridge->mode_valid() callbacks which will be used in followup patches.

Next, at 2/5 we modify the connector probe helper so that only modes which are supported by a given encoder+crtc combination are probbed.

At 3/5 a helper function is introduced that calls all mode_valid() from a set of bridges.

At 4/5 we call all the mode_valid() callbacks for a given pipeline so that the mode is validated. This is done before calling mode_fixup().

Finally, at 5/5 we use the new crtc->mode_valid() callback in arcpgu and remove the atomic_check() callback.

[1] https://patchwork.kernel.org/patch/9702233/

Jose Abreu (5):
drm: Add crtc/encoder/bridge->mode_valid() callbacks
drm: Use new mode_valid() helpers in connector probe helper
drm: Introduce drm_bridge_mode_valid()
drm: Use mode_valid() in atomic modeset
drm: arc: Use crtc->mode_valid() callback

Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>
 drivers/gpu/drm/arc/arcpgu_crtc.c        | 39 ++++++++------
 drivers/gpu/drm/drm_atomic_helper.c      | 92 ++++++++++++++++++++++++++++++--
 drivers/gpu/drm/drm_bridge.c             | 33 ++++++++++++
 drivers/gpu/drm/drm_probe_helper.c       | 71 ++++++++++++++++++++++--
 include/drm/drm_bridge.h                 | 22 ++++++++
 include/drm/drm_modeset_helper_vtables.h | 40 ++++++++++++++
 6 files changed, 275 insertions(+), 22 deletions(-)
Signature · 1 line
1.9.1
author
#1 lore raw

PATCH 1/5 drm: Add crtc/encoder/bridge->mode_valid() callbacks

This adds a new callback to crtc, encoder and bridge helper functions called mode_valid(). This callback shall be implemented if the corresponding component has some sort of restriction in the modes that can be displayed. A NULL callback implicates that the component can display all the modes.

Only the callbacks were implemented to simplify review process, following patches will make use of them.

Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>
---
 include/drm/drm_bridge.h                 | 20 ++++++++++++++++
 include/drm/drm_modeset_helper_vtables.h | 40 ++++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+)
include/drm/drm_bridge.h +20 -0
index fdd82fc..00c6c36 100644
@@ -59,6 +59,26 @@ struct drm_bridge_funcs {
 	void (*detach)(struct drm_bridge *bridge);
 
 	/**
+	 * @mode_valid:
+	 *
+	 * This callback is used to check if a specific mode is valid in this
+	 * bridge. This should be implemented if the bridge has some sort of
+	 * restriction in the modes it can display. For example, a given bridge
+	 * may be responsible to set a clock value. If the clock can not
+	 * produce all the values for the available modes then this callback
+	 * can be used to restrict the number of modes to only the ones that
+	 * can be displayed.
+	 *
+	 * This is called at mode probe and at atomic check phase.
+	 *
+	 * RETURNS:
+	 *
+	 * drm_mode_status Enum
+	 */
+	enum drm_mode_status (*mode_valid)(struct drm_bridge *crtc,
+					   const struct drm_display_mode *mode);
+
+	/**
 	 * @mode_fixup:
 	 *
 	 * This callback is used to validate and adjust a mode. The paramater
include/drm/drm_modeset_helper_vtables.h +40 -0
index c01c328..bb04688 100644
@@ -106,6 +106,26 @@ struct drm_crtc_helper_funcs {
 	void (*commit)(struct drm_crtc *crtc);
 
 	/**
+	 * @mode_valid:
+	 *
+	 * This callback is used to check if a specific mode is valid in this
+	 * crtc. This should be implemented if the crtc has some sort of
+	 * restriction in the modes it can display. For example, a given crtc
+	 * may be responsible to set a clock value. If the clock can not
+	 * produce all the values for the available modes then this callback
+	 * can be used to restrict the number of modes to only the ones that
+	 * can be displayed.
+	 *
+	 * This is called at mode probe and at atomic check phase.
+	 *
+	 * RETURNS:
+	 *
+	 * drm_mode_status Enum
+	 */
+	enum drm_mode_status (*mode_valid)(struct drm_crtc *crtc,
+					   const struct drm_display_mode *mode);
+
+	/**
 	 * @mode_fixup:
 	 *
 	 * This callback is used to validate a mode. The parameter mode is the
@@ -457,6 +477,26 @@ struct drm_encoder_helper_funcs {
 	void (*dpms)(struct drm_encoder *encoder, int mode);
 
 	/**
+	 * @mode_valid:
+	 *
+	 * This callback is used to check if a specific mode is valid in this
+	 * encoder. This should be implemented if the encoder has some sort
+	 * of restriction in the modes it can display. For example, a given
+	 * encoder may be responsible to set a clock value. If the clock can
+	 * not produce all the values for the available modes then this callback
+	 * can be used to restrict the number of modes to only the ones that
+	 * can be displayed.
+	 *
+	 * This is called at mode probe and at atomic check phase.
+	 *
+	 * RETURNS:
+	 *
+	 * drm_mode_status Enum
+	 */
+	enum drm_mode_status (*mode_valid)(struct drm_encoder *crtc,
+					   const struct drm_display_mode *mode);
+
+	/**
 	 * @mode_fixup:
 	 *
 	 * This callback is used to validate and adjust a mode. The parameter
Signature · 1 line
1.9.1
author
#3 lore raw

PATCH 2/5 drm: Use new mode_valid() helpers in connector probe helper

In reply to Jose Abreu

This changes the connector probe helper function to use the new encoder->mode_valid() and crtc->mode_valid() helper callbacks to validate the modes.

The new callbacks are optional so the behaviour remains the same if they are not implemented. If they are, then the code loops through all the connector's encodersXcrtcs and calls the callback.

If at least a valid encoderXcrtc combination is found which accepts the mode then the function returns MODE_OK.

Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>
---
 drivers/gpu/drm/drm_probe_helper.c | 71 +++++++++++++++++++++++++++++++++++---
 1 file changed, 67 insertions(+), 4 deletions(-)
drivers/gpu/drm/drm_probe_helper.c +67 -4
index 1b0c14a..bf19f82 100644
@@ -80,6 +80,67 @@
 	return MODE_OK;
 }
 
+static enum drm_mode_status
+drm_mode_validate_connector(struct drm_connector *connector,
+			    struct drm_display_mode *mode)
+{
+	const struct drm_connector_helper_funcs *connector_funcs =
+		connector->helper_private;
+	struct drm_device *dev = connector->dev;
+	uint32_t *ids = connector->encoder_ids;
+	enum drm_mode_status ret = MODE_OK;
+	unsigned int i;
+
+	/* Step 1: Validate against connector */
+	if (connector_funcs && connector_funcs->mode_valid)
+		ret = connector_funcs->mode_valid(connector, mode);
+
+	if (ret != MODE_OK)
+		return ret;
+
+	/* Step 2: Validate against encoders and crtcs */
+	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
+		struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
+		const struct drm_encoder_helper_funcs *encoder_funcs;
+		struct drm_crtc *crtc;
+
+		if (!encoder)
+			continue;
+
+		encoder_funcs = encoder->helper_private;
+		if (encoder_funcs && encoder_funcs->mode_valid)
+			ret = encoder_funcs->mode_valid(encoder, mode);
+		else
+			ret = MODE_OK; /* encoder accepts everything */
+
+		/* No point in continuing for crtc check as this encoder will
+		 * not accept the mode anyway. If all encoders reject the mode
+		 * then, at exit, ret will not be MODE_OK. */
+		if (ret != MODE_OK)
+			continue;
+
+		drm_for_each_crtc(crtc, dev) {
+			const struct drm_crtc_helper_funcs *crtc_funcs;
+
+			if (!drm_encoder_crtc_ok(encoder, crtc))
+				continue;
+
+			crtc_funcs = crtc->helper_private;
+			if (!crtc_funcs || !crtc_funcs->mode_valid)
+				return MODE_OK; /* crtc accepts everything */
+
+			ret = crtc_funcs->mode_valid(crtc, mode);
+			if (ret == MODE_OK)
+				/* If we get to this point there is at least
+				 * one combination of encoder+crtc that works
+				 * for this mode. Lets return now. */
+				return ret;
+		}
+	}
+
+	return ret;
+}
+
 static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
 {
 	struct drm_cmdline_mode *cmdline_mode;
@@ -283,8 +344,10 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
  *      (if specified)
  *    - drm_mode_validate_flag() checks the modes against basic connector
  *      capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
- *    - the optional &drm_connector_helper_funcs.mode_valid helper can perform
- *      driver and/or hardware specific checks
+ *    - the optional &drm_connector_helper_funcs.mode_valid,
+ *    	&drm_crtc_helper_funcs.mode_valid and
+ *    	&drm_encoder_helper_funcs.mode_valid helpers can perform driver and/or
+ *    	hardware specific checks
  *
  * 5. Any mode whose status is not OK is pruned from the connector's modes list,
  *    accompanied by a debug message indicating the reason for the mode's
@@ -428,8 +491,8 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 		if (mode->status == MODE_OK)
 			mode->status = drm_mode_validate_flag(mode, mode_flags);
 
-		if (mode->status == MODE_OK && connector_funcs->mode_valid)
-			mode->status = connector_funcs->mode_valid(connector,
+		if (mode->status == MODE_OK)
+			mode->status = drm_mode_validate_connector(connector,
 								   mode);
 	}
 
Signature · 1 line
1.9.1
author
#9 lore raw

PATCH 3/5 drm: Introduce drm_bridge_mode_valid()

In reply to Jose Abreu

Introduce a new helper function which calls mode_valid() callback for all bridges in an encoder chain.

Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>
---
 drivers/gpu/drm/drm_bridge.c | 33 +++++++++++++++++++++++++++++++++
 include/drm/drm_bridge.h     |  2 ++
 2 files changed, 35 insertions(+)
drivers/gpu/drm/drm_bridge.c +33 -0
index 86a7637..dc8cdfe 100644
@@ -206,6 +206,39 @@ bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
 EXPORT_SYMBOL(drm_bridge_mode_fixup);
 
 /**
+ * drm_bridge_mode_valid - validate the mode against all bridges in the
+ * 			   encoder chain.
+ * @bridge: bridge control structure
+ * @mode: desired mode to be validated
+ *
+ * Calls &drm_bridge_funcs.mode_valid for all the bridges in the encoder
+ * chain, starting from the first bridge to the last. If at least one bridge
+ * does not accept the mode the function returns the error code.
+ *
+ * Note: the bridge passed should be the one closest to the encoder.
+ *
+ * RETURNS:
+ * MODE_OK on success, drm_mode_status Enum error code on failure
+ */
+enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
+					   const struct drm_display_mode *mode)
+{
+	enum drm_mode_status ret = MODE_OK;
+
+	if (!bridge)
+		return ret;
+
+	if (bridge->funcs->mode_valid)
+		ret = bridge->funcs->mode_valid(bridge, mode);
+
+	if (ret != MODE_OK)
+		return ret;
+
+	return drm_bridge_mode_valid(bridge->next, mode);
+}
+EXPORT_SYMBOL(drm_bridge_mode_valid);
+
+/**
  * drm_bridge_disable - disables all bridges in the encoder chain
  * @bridge: bridge control structure
  *
include/drm/drm_bridge.h +2 -0
index 00c6c36..8358eb3 100644
@@ -233,6 +233,8 @@ int drm_bridge_attach(struct drm_encoder *encoder, struct drm_bridge *bridge,
 bool drm_bridge_mode_fixup(struct drm_bridge *bridge,
 			const struct drm_display_mode *mode,
 			struct drm_display_mode *adjusted_mode);
+enum drm_mode_status drm_bridge_mode_valid(struct drm_bridge *bridge,
+					   const struct drm_display_mode *mode);
 void drm_bridge_disable(struct drm_bridge *bridge);
 void drm_bridge_post_disable(struct drm_bridge *bridge);
 void drm_bridge_mode_set(struct drm_bridge *bridge,
Signature · 1 line
1.9.1
author
#10 lore raw

PATCH 4/5 drm: Use mode_valid() in atomic modeset

In reply to Jose Abreu

This patches makes use of the new mode_valid() callbacks introduced previously to validate the full video pipeline when modesetting.

This calls the connector->mode_valid(), encoder->mode_valid(), bridge->mode_valid() and crtc->mode_valid() so that we can make sure that the mode will be accepted in every components.

Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>
---
 drivers/gpu/drm/drm_atomic_helper.c | 92 +++++++++++++++++++++++++++++++++++--
 1 file changed, 89 insertions(+), 3 deletions(-)
drivers/gpu/drm/drm_atomic_helper.c +89 -3
index 8be9719..6eb305d 100644
@@ -452,6 +452,85 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state,
 	return 0;
 }
 
+static enum drm_mode_status mode_valid_pipe(struct drm_connector *connector,
+					    struct drm_encoder *encoder,
+					    struct drm_crtc *crtc,
+					    struct drm_display_mode *mode)
+{
+	const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
+	const struct drm_connector_helper_funcs *connector_funcs =
+		connector->helper_private;
+	const struct drm_encoder_helper_funcs *encoder_funcs =
+		encoder->helper_private;
+	enum drm_mode_status ret = MODE_OK;
+
+	if (connector_funcs && connector_funcs->mode_valid)
+		ret = connector_funcs->mode_valid(connector, mode);
+
+	if (ret != MODE_OK) {
+		DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] mode_valid() failed\n",
+				connector->base.id, connector->name);
+		return ret;
+	}
+
+	if (encoder_funcs && encoder_funcs->mode_valid)
+		ret = encoder_funcs->mode_valid(encoder, mode);
+
+	if (ret != MODE_OK) {
+		DRM_DEBUG_ATOMIC("[ENCODER:%d:%s] mode_valid() failed\n",
+				encoder->base.id, encoder->name);
+		return ret;
+	}
+
+	ret = drm_bridge_mode_valid(encoder->bridge, mode);
+	if (ret != MODE_OK) {
+		DRM_DEBUG_ATOMIC("[BRIDGE] mode_valid() failed\n");
+		return ret;
+	}
+
+	if (crtc_funcs && crtc_funcs->mode_valid)
+		ret = crtc_funcs->mode_valid(crtc, mode);
+
+	if (ret != MODE_OK) {
+		DRM_DEBUG_ATOMIC("[CRTC:%d:%s] mode_valid() failed\n",
+				crtc->base.id, crtc->name);
+		return ret;
+	}
+
+	return ret;
+}
+
+static int
+mode_valid(struct drm_atomic_state *state)
+{
+	struct drm_connector_state *conn_state;
+	struct drm_connector *connector;
+	int i;
+
+	for_each_connector_in_state(state, connector, conn_state, i) {
+		struct drm_encoder *encoder = conn_state->best_encoder;
+		struct drm_crtc *crtc = conn_state->crtc;
+		struct drm_crtc_state *crtc_state;
+		enum drm_mode_status mode_status;
+		struct drm_display_mode *mode;
+
+		if (!crtc || !encoder)
+			continue;
+
+		crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
+		if (!crtc_state)
+			continue;
+
+		mode = &crtc_state->mode;
+
+		mode_status = mode_valid_pipe(connector, encoder, crtc, mode);
+		if (mode_status != MODE_OK)
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
 /**
  * drm_atomic_helper_check_modeset - validate state object for modeset changes
  * @dev: DRM device
@@ -466,13 +545,16 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state,
  * 2. &drm_connector_helper_funcs.atomic_check to validate the connector state.
  * 3. If it's determined a modeset is needed then all connectors on the affected crtc
  *    crtc are added and &drm_connector_helper_funcs.atomic_check is run on them.
- * 4. &drm_bridge_funcs.mode_fixup is called on all encoder bridges.
- * 5. &drm_encoder_helper_funcs.atomic_check is called to validate any encoder state.
+ * 4. &drm_connector_helper_funcs.mode_valid, &drm_encoder_helper_funcs.mode_valid,
+ *    &drm_bridge_funcs.mode_valid and &drm_crtc_helper_funcs.mode_valid are called
+ *    on the affected components.
+ * 5. &drm_bridge_funcs.mode_fixup is called on all encoder bridges.
+ * 6. &drm_encoder_helper_funcs.atomic_check is called to validate any encoder state.
  *    This function is only called when the encoder will be part of a configured crtc,
  *    it must not be used for implementing connector property validation.
  *    If this function is NULL, &drm_atomic_encoder_helper_funcs.mode_fixup is called
  *    instead.
- * 6. &drm_crtc_helper_funcs.mode_fixup is called last, to fix up the mode with crtc constraints.
+ * 7. &drm_crtc_helper_funcs.mode_fixup is called last, to fix up the mode with crtc constraints.
  *
  * &drm_crtc_state.mode_changed is set when the input mode is changed.
  * &drm_crtc_state.connectors_changed is set when a connector is added or
@@ -617,6 +699,10 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state,
 			return ret;
 	}
 
+	ret = mode_valid(state);
+	if (ret)
+		return ret;
+
 	return mode_fixup(state);
 }
 EXPORT_SYMBOL(drm_atomic_helper_check_modeset);
Signature · 1 line
1.9.1
author
#14 lore raw

PATCH 5/5 drm: arc: Use crtc->mode_valid() callback

In reply to Jose Abreu

Now that we have a callback to check if crtc supports a given mode we can use it in arcpgu so that we restrict the number of probbed modes to the ones we can actually display.

This is specially useful because arcpgu crtc is responsible to set a clock value in the commit() stage but unfortunatelly this clock does not support all the needed ranges.

Also, remove the atomic_check() callback as mode_valid() callback will be called before.

Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>
---
 drivers/gpu/drm/arc/arcpgu_crtc.c | 39 ++++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 15 deletions(-)
drivers/gpu/drm/arc/arcpgu_crtc.c +24 -15
index ad9a959..01cae0a 100644
@@ -32,6 +32,18 @@
 	{ "r8g8b8", 24, {16, 8}, {8, 8}, {0, 8}, {0, 0}, DRM_FORMAT_RGB888 },
 };
 
+static bool arc_pgu_is_mode_valid(struct arcpgu_drm_private *arcpgu,
+				  const struct drm_display_mode *mode)
+{
+	long rate, clk_rate = mode->clock * 1000;
+
+	rate = clk_round_rate(arcpgu->clk, clk_rate);
+	if (rate != clk_rate)
+		return false;
+
+	return true;
+}
+
 static void arc_pgu_set_pxl_fmt(struct drm_crtc *crtc)
 {
 	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
@@ -64,6 +76,17 @@ static void arc_pgu_set_pxl_fmt(struct drm_crtc *crtc)
 	.atomic_destroy_state = drm_atomic_helper_crtc_destroy_state,
 };
 
+enum drm_mode_status arc_pgu_crtc_mode_valid(struct drm_crtc *crtc,
+					     const struct drm_display_mode *mode)
+{
+	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
+
+	if (!arc_pgu_is_mode_valid(arcpgu, mode))
+		return MODE_NOCLOCK;
+
+	return MODE_OK;
+}
+
 static void arc_pgu_crtc_mode_set_nofb(struct drm_crtc *crtc)
 {
 	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
@@ -129,20 +152,6 @@ static void arc_pgu_crtc_disable(struct drm_crtc *crtc)
 			      ~ARCPGU_CTRL_ENABLE_MASK);
 }
 
-static int arc_pgu_crtc_atomic_check(struct drm_crtc *crtc,
-				     struct drm_crtc_state *state)
-{
-	struct arcpgu_drm_private *arcpgu = crtc_to_arcpgu_priv(crtc);
-	struct drm_display_mode *mode = &state->adjusted_mode;
-	long rate, clk_rate = mode->clock * 1000;
-
-	rate = clk_round_rate(arcpgu->clk, clk_rate);
-	if (rate != clk_rate)
-		return -EINVAL;
-
-	return 0;
-}
-
 static void arc_pgu_crtc_atomic_begin(struct drm_crtc *crtc,
 				      struct drm_crtc_state *state)
 {
@@ -158,6 +167,7 @@ static void arc_pgu_crtc_atomic_begin(struct drm_crtc *crtc,
 }
 
 static const struct drm_crtc_helper_funcs arc_pgu_crtc_helper_funcs = {
+	.mode_valid	= arc_pgu_crtc_mode_valid,
 	.mode_set	= drm_helper_crtc_mode_set,
 	.mode_set_base	= drm_helper_crtc_mode_set_base,
 	.mode_set_nofb	= arc_pgu_crtc_mode_set_nofb,
@@ -165,7 +175,6 @@ static void arc_pgu_crtc_atomic_begin(struct drm_crtc *crtc,
 	.disable	= arc_pgu_crtc_disable,
 	.prepare	= arc_pgu_crtc_disable,
 	.commit		= arc_pgu_crtc_enable,
-	.atomic_check	= arc_pgu_crtc_atomic_check,
 	.atomic_begin	= arc_pgu_crtc_atomic_begin,
 };
 
Signature · 1 line
1.9.1
#4 lore raw

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

In reply to Jose Abreu
Quoted 54 lines · Jose Abreu

This changes the connector probe helper function to use the new encoder->mode_valid() and crtc->mode_valid() helper callbacks to validate the modes.

The new callbacks are optional so the behaviour remains the same if they are not implemented. If they are, then the code loops through all the connector's encodersXcrtcs and calls the callback.

If at least a valid encoderXcrtc combination is found which accepts the mode then the function returns MODE_OK.

Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>
---
 drivers/gpu/drm/drm_probe_helper.c | 71 +++++++++++++++++++++++++++++++++++---
 1 file changed, 67 insertions(+), 4 deletions(-)
drivers/gpu/drm/drm_probe_helper.c +22 -0
index 1b0c14a..bf19f82 100644
@@ -80,6 +80,67 @@
 	return MODE_OK;
 }
 
+static enum drm_mode_status
+drm_mode_validate_connector(struct drm_connector *connector,
+			    struct drm_display_mode *mode)
+{
+	const struct drm_connector_helper_funcs *connector_funcs =
+		connector->helper_private;
+	struct drm_device *dev = connector->dev;
+	uint32_t *ids = connector->encoder_ids;
+	enum drm_mode_status ret = MODE_OK;
+	unsigned int i;
+
+	/* Step 1: Validate against connector */
+	if (connector_funcs && connector_funcs->mode_valid)
+		ret = connector_funcs->mode_valid(connector, mode);
+
+	if (ret != MODE_OK)
+		return ret;
+
+	/* Step 2: Validate against encoders and crtcs */
+	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
+		struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
+		const struct drm_encoder_helper_funcs *encoder_funcs;

drivers/gpu/drm/drm_probe_helper.c line 114

Quoted 10 lines
drivers/gpu/drm/drm_probe_helper.c +10 -0
+		struct drm_crtc *crtc;
+
+		if (!encoder)
+			continue;
+
+		encoder_funcs = encoder->helper_private;
+		if (encoder_funcs && encoder_funcs->mode_valid)
+			ret = encoder_funcs->mode_valid(encoder, mode);
+		else
+			ret = MODE_OK; /* encoder accepts everything */

Since you already added the drm_bridge_mode_valid() helper, maybe add one for connectors, encoders and crtcs as well. Might keep the logic in this function a bit more clear on account of not having to check for the presence of the vfunc. Right now all three cases look slightly different from one another.

Quoted 59 lines
drivers/gpu/drm/drm_probe_helper.c +35 -4
+
+		/* No point in continuing for crtc check as this encoder will
+		 * not accept the mode anyway. If all encoders reject the mode
+		 * then, at exit, ret will not be MODE_OK. */
+		if (ret != MODE_OK)
+			continue;
+
+		drm_for_each_crtc(crtc, dev) {
+			const struct drm_crtc_helper_funcs *crtc_funcs;
+
+			if (!drm_encoder_crtc_ok(encoder, crtc))
+				continue;
+
+			crtc_funcs = crtc->helper_private;
+			if (!crtc_funcs || !crtc_funcs->mode_valid)
+				return MODE_OK; /* crtc accepts everything */
+
+			ret = crtc_funcs->mode_valid(crtc, mode);
+			if (ret == MODE_OK)
+				/* If we get to this point there is at least
+				 * one combination of encoder+crtc that works
+				 * for this mode. Lets return now. */
+				return ret;
+		}
+	}
+
+	return ret;
+}
+
 static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
 {
 	struct drm_cmdline_mode *cmdline_mode;
@@ -283,8 +344,10 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
  *      (if specified)
  *    - drm_mode_validate_flag() checks the modes against basic connector
  *      capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
- *    - the optional &drm_connector_helper_funcs.mode_valid helper can perform
- *      driver and/or hardware specific checks
+ *    - the optional &drm_connector_helper_funcs.mode_valid,
+ *    	&drm_crtc_helper_funcs.mode_valid and
+ *    	&drm_encoder_helper_funcs.mode_valid helpers can perform driver and/or
+ *    	hardware specific checks
  *
  * 5. Any mode whose status is not OK is pruned from the connector's modes list,
  *    accompanied by a debug message indicating the reason for the mode's
@@ -428,8 +491,8 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 		if (mode->status == MODE_OK)
 			mode->status = drm_mode_validate_flag(mode, mode_flags);
 
-		if (mode->status == MODE_OK && connector_funcs->mode_valid)
-			mode->status = connector_funcs->mode_valid(connector,
+		if (mode->status == MODE_OK)
+			mode->status = drm_mode_validate_connector(connector,
 								   mode);
 	}
 
Signature · 1 line
1.9.1
Signature · 2 lines
Ville Syrjälä
Intel OTC
#11 lore raw

Re: [PATCH 4/5] drm: Use mode_valid() in atomic modeset

In reply to Jose Abreu
Quoted 24 lines · Jose Abreu

This patches makes use of the new mode_valid() callbacks introduced previously to validate the full video pipeline when modesetting.

This calls the connector->mode_valid(), encoder->mode_valid(), bridge->mode_valid() and crtc->mode_valid() so that we can make sure that the mode will be accepted in every components.

Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>
---
 drivers/gpu/drm/drm_atomic_helper.c | 92 +++++++++++++++++++++++++++++++++++--
 1 file changed, 89 insertions(+), 3 deletions(-)
drivers/gpu/drm/drm_atomic_helper.c +0 -0
index 8be9719..6eb305d 100644

drivers/gpu/drm/drm_atomic_helper.c static int handle_conflicting_encoders(struct drm_atomic_state *state, · line 455

Quoted 4 lines
drivers/gpu/drm/drm_atomic_helper.c +1 -0
@@ -452,6 +452,85 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state,
 	return 0;
 }
 
+static enum drm_mode_status mode_valid_pipe(struct drm_connector *connector,

The name feels off. Pipe means crtc for i915, and for drm_irq.c as well.

drivers/gpu/drm/drm_atomic_helper.c static int handle_conflicting_encoders(struct drm_atomic_state *state, · line 468

Quoted 13 lines
drivers/gpu/drm/drm_atomic_helper.c +13 -0
+					    struct drm_encoder *encoder,
+					    struct drm_crtc *crtc,
+					    struct drm_display_mode *mode)
+{
+	const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
+	const struct drm_connector_helper_funcs *connector_funcs =
+		connector->helper_private;
+	const struct drm_encoder_helper_funcs *encoder_funcs =
+		encoder->helper_private;
+	enum drm_mode_status ret = MODE_OK;
+
+	if (connector_funcs && connector_funcs->mode_valid)
+		ret = connector_funcs->mode_valid(connector, mode);

As I mentioned earlier, this would break i915. We either can't call the connector hook at all here, or we have to make it somehow opt-in if some drivers really want to do it.

Quoted 32 lines
drivers/gpu/drm/drm_atomic_helper.c +32 -0
+
+	if (ret != MODE_OK) {
+		DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] mode_valid() failed\n",
+				connector->base.id, connector->name);
+		return ret;
+	}
+
+	if (encoder_funcs && encoder_funcs->mode_valid)
+		ret = encoder_funcs->mode_valid(encoder, mode);
+
+	if (ret != MODE_OK) {
+		DRM_DEBUG_ATOMIC("[ENCODER:%d:%s] mode_valid() failed\n",
+				encoder->base.id, encoder->name);
+		return ret;
+	}
+
+	ret = drm_bridge_mode_valid(encoder->bridge, mode);
+	if (ret != MODE_OK) {
+		DRM_DEBUG_ATOMIC("[BRIDGE] mode_valid() failed\n");
+		return ret;
+	}
+
+	if (crtc_funcs && crtc_funcs->mode_valid)
+		ret = crtc_funcs->mode_valid(crtc, mode);
+
+	if (ret != MODE_OK) {
+		DRM_DEBUG_ATOMIC("[CRTC:%d:%s] mode_valid() failed\n",
+				crtc->base.id, crtc->name);
+		return ret;
+	}
+
+	return ret;

drivers/gpu/drm/drm_atomic_helper.c static int handle_conflicting_encoders(struct drm_atomic_state *state, · line 510

Quoted 10 lines
drivers/gpu/drm/drm_atomic_helper.c +10 -0
+}
+
+static int
+mode_valid(struct drm_atomic_state *state)
+{
+	struct drm_connector_state *conn_state;
+	struct drm_connector *connector;
+	int i;
+
+	for_each_connector_in_state(state, connector, conn_state, i) {

for_each_new...

drivers/gpu/drm/drm_atomic_helper.c static int handle_conflicting_encoders(struct drm_atomic_state *state, · line 522

Quoted 12 lines
drivers/gpu/drm/drm_atomic_helper.c +12 -0
+		struct drm_encoder *encoder = conn_state->best_encoder;
+		struct drm_crtc *crtc = conn_state->crtc;
+		struct drm_crtc_state *crtc_state;
+		enum drm_mode_status mode_status;
+		struct drm_display_mode *mode;
+
+		if (!crtc || !encoder)
+			continue;
+
+		crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
+		if (!crtc_state)
+			continue;

Maybe?

if (!mode_changed && !connectors_changed)

	continue;

drivers/gpu/drm/drm_atomic_helper.c static int handle_conflicting_encoders(struct drm_atomic_state *state, · line 524

Quoted 2 lines
drivers/gpu/drm/drm_atomic_helper.c +2 -0
+
+		mode = &crtc_state->mode;

Seems like a fairly pointless variable.

Quoted 46 lines
drivers/gpu/drm/drm_atomic_helper.c +19 -3
+
+		mode_status = mode_valid_pipe(connector, encoder, crtc, mode);
+		if (mode_status != MODE_OK)
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
 /**
  * drm_atomic_helper_check_modeset - validate state object for modeset changes
  * @dev: DRM device
@@ -466,13 +545,16 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state,
  * 2. &drm_connector_helper_funcs.atomic_check to validate the connector state.
  * 3. If it's determined a modeset is needed then all connectors on the affected crtc
  *    crtc are added and &drm_connector_helper_funcs.atomic_check is run on them.
- * 4. &drm_bridge_funcs.mode_fixup is called on all encoder bridges.
- * 5. &drm_encoder_helper_funcs.atomic_check is called to validate any encoder state.
+ * 4. &drm_connector_helper_funcs.mode_valid, &drm_encoder_helper_funcs.mode_valid,
+ *    &drm_bridge_funcs.mode_valid and &drm_crtc_helper_funcs.mode_valid are called
+ *    on the affected components.
+ * 5. &drm_bridge_funcs.mode_fixup is called on all encoder bridges.
+ * 6. &drm_encoder_helper_funcs.atomic_check is called to validate any encoder state.
  *    This function is only called when the encoder will be part of a configured crtc,
  *    it must not be used for implementing connector property validation.
  *    If this function is NULL, &drm_atomic_encoder_helper_funcs.mode_fixup is called
  *    instead.
- * 6. &drm_crtc_helper_funcs.mode_fixup is called last, to fix up the mode with crtc constraints.
+ * 7. &drm_crtc_helper_funcs.mode_fixup is called last, to fix up the mode with crtc constraints.
  *
  * &drm_crtc_state.mode_changed is set when the input mode is changed.
  * &drm_crtc_state.connectors_changed is set when a connector is added or
@@ -617,6 +699,10 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state,
 			return ret;
 	}
 
+	ret = mode_valid(state);
+	if (ret)
+		return ret;
+
 	return mode_fixup(state);
 }
 EXPORT_SYMBOL(drm_atomic_helper_check_modeset);
Signature · 1 line
1.9.1
Signature · 2 lines
Ville Syrjälä
Intel OTC
author
#5 lore raw

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

In reply to Ville Syrjälä

Hi Ville,

Quoted 62 lines · Ville Syrjälä
Quoted 61 lines · Jose Abreu

This changes the connector probe helper function to use the new encoder->mode_valid() and crtc->mode_valid() helper callbacks to validate the modes.

The new callbacks are optional so the behaviour remains the same if they are not implemented. If they are, then the code loops through all the connector's encodersXcrtcs and calls the callback.

If at least a valid encoderXcrtc combination is found which accepts the mode then the function returns MODE_OK.

Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>
---
 drivers/gpu/drm/drm_probe_helper.c | 71 +++++++++++++++++++++++++++++++++++---
 1 file changed, 67 insertions(+), 4 deletions(-)
drivers/gpu/drm/drm_probe_helper.c +29 -0
index 1b0c14a..bf19f82 100644
@@ -80,6 +80,67 @@
 	return MODE_OK;
 }
 
+static enum drm_mode_status
+drm_mode_validate_connector(struct drm_connector *connector,
+			    struct drm_display_mode *mode)
+{
+	const struct drm_connector_helper_funcs *connector_funcs =
+		connector->helper_private;
+	struct drm_device *dev = connector->dev;
+	uint32_t *ids = connector->encoder_ids;
+	enum drm_mode_status ret = MODE_OK;
+	unsigned int i;
+
+	/* Step 1: Validate against connector */
+	if (connector_funcs && connector_funcs->mode_valid)
+		ret = connector_funcs->mode_valid(connector, mode);
+
+	if (ret != MODE_OK)
+		return ret;
+
+	/* Step 2: Validate against encoders and crtcs */
+	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
+		struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
+		const struct drm_encoder_helper_funcs *encoder_funcs;
+		struct drm_crtc *crtc;
+
+		if (!encoder)
+			continue;
+
+		encoder_funcs = encoder->helper_private;
+		if (encoder_funcs && encoder_funcs->mode_valid)
Quoted 8 lines

drivers/gpu/drm/drm_probe_helper.c line 114

Quoted 3 lines
drivers/gpu/drm/drm_probe_helper.c +3 -0
+			ret = encoder_funcs->mode_valid(encoder, mode);
+		else
+			ret = MODE_OK; /* encoder accepts everything */

Since you already added the drm_bridge_mode_valid() helper, maybe add one for connectors, encoders and crtcs as well. Might keep the logic in this function a bit more clear on account of not having to check for the presence of the vfunc. Right now all three cases look slightly different from one another.

Ok, will add in next version. Thanks!

Best regards,
Jose Miguel Abreu

Quoted 60 lines
Quoted 60 lines
drivers/gpu/drm/drm_probe_helper.c +35 -4
+
+		/* No point in continuing for crtc check as this encoder will
+		 * not accept the mode anyway. If all encoders reject the mode
+		 * then, at exit, ret will not be MODE_OK. */
+		if (ret != MODE_OK)
+			continue;
+
+		drm_for_each_crtc(crtc, dev) {
+			const struct drm_crtc_helper_funcs *crtc_funcs;
+
+			if (!drm_encoder_crtc_ok(encoder, crtc))
+				continue;
+
+			crtc_funcs = crtc->helper_private;
+			if (!crtc_funcs || !crtc_funcs->mode_valid)
+				return MODE_OK; /* crtc accepts everything */
+
+			ret = crtc_funcs->mode_valid(crtc, mode);
+			if (ret == MODE_OK)
+				/* If we get to this point there is at least
+				 * one combination of encoder+crtc that works
+				 * for this mode. Lets return now. */
+				return ret;
+		}
+	}
+
+	return ret;
+}
+
 static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
 {
 	struct drm_cmdline_mode *cmdline_mode;
@@ -283,8 +344,10 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
  *      (if specified)
  *    - drm_mode_validate_flag() checks the modes against basic connector
  *      capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
- *    - the optional &drm_connector_helper_funcs.mode_valid helper can perform
- *      driver and/or hardware specific checks
+ *    - the optional &drm_connector_helper_funcs.mode_valid,
+ *    	&drm_crtc_helper_funcs.mode_valid and
+ *    	&drm_encoder_helper_funcs.mode_valid helpers can perform driver and/or
+ *    	hardware specific checks
  *
  * 5. Any mode whose status is not OK is pruned from the connector's modes list,
  *    accompanied by a debug message indicating the reason for the mode's
@@ -428,8 +491,8 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 		if (mode->status == MODE_OK)
 			mode->status = drm_mode_validate_flag(mode, mode_flags);
 
-		if (mode->status == MODE_OK && connector_funcs->mode_valid)
-			mode->status = connector_funcs->mode_valid(connector,
+		if (mode->status == MODE_OK)
+			mode->status = drm_mode_validate_connector(connector,
 								   mode);
 	}
 
Signature · 1 line
1.9.1
author
#12 lore raw

Re: [PATCH 4/5] drm: Use mode_valid() in atomic modeset

In reply to Ville Syrjälä

Hi Ville,

Quoted 28 lines · Ville Syrjälä
Quoted 27 lines · Jose Abreu

This patches makes use of the new mode_valid() callbacks introduced previously to validate the full video pipeline when modesetting.

This calls the connector->mode_valid(), encoder->mode_valid(), bridge->mode_valid() and crtc->mode_valid() so that we can make sure that the mode will be accepted in every components.

Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>
---
 drivers/gpu/drm/drm_atomic_helper.c | 92 +++++++++++++++++++++++++++++++++++--
 1 file changed, 89 insertions(+), 3 deletions(-)
drivers/gpu/drm/drm_atomic_helper.c +0 -0
index 8be9719..6eb305d 100644
@@ -452,6 +452,85 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state,
 	return 0;
 }
 
Quoted 2 lines

drivers/gpu/drm/drm_atomic_helper.c static int handle_conflicting_encoders(struct drm_atomic_state *state, · line 455

Quoted 1 line
drivers/gpu/drm/drm_atomic_helper.c +1 -0
+static enum drm_mode_status mode_valid_pipe(struct drm_connector *connector,

The name feels off. Pipe means crtc for i915, and for drm_irq.c as well.

Hmmm, mode_valid_path, mode_valid_components ?

Quoted 17 lines
Quoted 4 lines
drivers/gpu/drm/drm_atomic_helper.c +3 -0
+					    struct drm_encoder *encoder,
+					    struct drm_crtc *crtc,
+					    struct drm_display_mode *mode)

drivers/gpu/drm/drm_atomic_helper.c static int handle_conflicting_encoders(struct drm_atomic_state *state, · line 468

Quoted 10 lines
drivers/gpu/drm/drm_atomic_helper.c +10 -0
+{
+	const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
+	const struct drm_connector_helper_funcs *connector_funcs =
+		connector->helper_private;
+	const struct drm_encoder_helper_funcs *encoder_funcs =
+		encoder->helper_private;
+	enum drm_mode_status ret = MODE_OK;
+
+	if (connector_funcs && connector_funcs->mode_valid)
+		ret = connector_funcs->mode_valid(connector, mode);

As I mentioned earlier, this would break i915. We either can't call the connector hook at all here, or we have to make it somehow opt-in if some drivers really want to do it.

Ok. You said you let users exceed the limits, but why doesn't it fail in atomic_check and will fail in mode_valid? I guess I can remove it, but this can lead to lots of confusion, i.e. with this series the mode_valid callbacks for all components are called, if I remove just one call the whole point will fall apart.

Can we think about something else ? I think making it opt-in is not ideal, if the helper is there then it should be used, but if thats the best solution then shall we add a flag which will call or not *all* the mode_valid callbacks in this stage (drm_device.allow_modevalid_call, ...) ?

Quoted 36 lines
Quoted 36 lines
drivers/gpu/drm/drm_atomic_helper.c +35 -0
+
+	if (ret != MODE_OK) {
+		DRM_DEBUG_ATOMIC("[CONNECTOR:%d:%s] mode_valid() failed\n",
+				connector->base.id, connector->name);
+		return ret;
+	}
+
+	if (encoder_funcs && encoder_funcs->mode_valid)
+		ret = encoder_funcs->mode_valid(encoder, mode);
+
+	if (ret != MODE_OK) {
+		DRM_DEBUG_ATOMIC("[ENCODER:%d:%s] mode_valid() failed\n",
+				encoder->base.id, encoder->name);
+		return ret;
+	}
+
+	ret = drm_bridge_mode_valid(encoder->bridge, mode);
+	if (ret != MODE_OK) {
+		DRM_DEBUG_ATOMIC("[BRIDGE] mode_valid() failed\n");
+		return ret;
+	}
+
+	if (crtc_funcs && crtc_funcs->mode_valid)
+		ret = crtc_funcs->mode_valid(crtc, mode);
+
+	if (ret != MODE_OK) {
+		DRM_DEBUG_ATOMIC("[CRTC:%d:%s] mode_valid() failed\n",
+				crtc->base.id, crtc->name);
+		return ret;
+	}
+
+	return ret;
+}
+
+static int
Quoted 8 lines

drivers/gpu/drm/drm_atomic_helper.c static int handle_conflicting_encoders(struct drm_atomic_state *state, · line 510

Quoted 7 lines
drivers/gpu/drm/drm_atomic_helper.c +7 -0
+mode_valid(struct drm_atomic_state *state)
+{
+	struct drm_connector_state *conn_state;
+	struct drm_connector *connector;
+	int i;
+
+	for_each_connector_in_state(state, connector, conn_state, i) {

for_each_new...

Ok.

Quoted 16 lines

drivers/gpu/drm/drm_atomic_helper.c static int handle_conflicting_encoders(struct drm_atomic_state *state, · line 522

Quoted 13 lines
drivers/gpu/drm/drm_atomic_helper.c +12 -0
+		struct drm_encoder *encoder = conn_state->best_encoder;
+		struct drm_crtc *crtc = conn_state->crtc;
+		struct drm_crtc_state *crtc_state;
+		enum drm_mode_status mode_status;
+		struct drm_display_mode *mode;
+
+		if (!crtc || !encoder)
+			continue;
+
+		crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
+		if (!crtc_state)
+			continue;

Maybe?

Quoted 2 lines

if (!mode_changed && !connectors_changed)

	continue;

Yes, no point in checking if the mode and connector didn't change.

Quoted 4 lines

drivers/gpu/drm/drm_atomic_helper.c static int handle_conflicting_encoders(struct drm_atomic_state *state, · line 524

Quoted 3 lines
drivers/gpu/drm/drm_atomic_helper.c +2 -0
+
+		mode = &crtc_state->mode;

Seems like a fairly pointless variable.

Yeah, this was to avoid the next function call to exceed 80 chars, I don't really like line breaks :) Thanks for the review!

Best regards,
Jose Miguel Abreu

Quoted 47 lines
Quoted 47 lines
drivers/gpu/drm/drm_atomic_helper.c +19 -3
+
+		mode_status = mode_valid_pipe(connector, encoder, crtc, mode);
+		if (mode_status != MODE_OK)
+			return -EINVAL;
+	}
+
+	return 0;
+}
+
 /**
  * drm_atomic_helper_check_modeset - validate state object for modeset changes
  * @dev: DRM device
@@ -466,13 +545,16 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state,
  * 2. &drm_connector_helper_funcs.atomic_check to validate the connector state.
  * 3. If it's determined a modeset is needed then all connectors on the affected crtc
  *    crtc are added and &drm_connector_helper_funcs.atomic_check is run on them.
- * 4. &drm_bridge_funcs.mode_fixup is called on all encoder bridges.
- * 5. &drm_encoder_helper_funcs.atomic_check is called to validate any encoder state.
+ * 4. &drm_connector_helper_funcs.mode_valid, &drm_encoder_helper_funcs.mode_valid,
+ *    &drm_bridge_funcs.mode_valid and &drm_crtc_helper_funcs.mode_valid are called
+ *    on the affected components.
+ * 5. &drm_bridge_funcs.mode_fixup is called on all encoder bridges.
+ * 6. &drm_encoder_helper_funcs.atomic_check is called to validate any encoder state.
  *    This function is only called when the encoder will be part of a configured crtc,
  *    it must not be used for implementing connector property validation.
  *    If this function is NULL, &drm_atomic_encoder_helper_funcs.mode_fixup is called
  *    instead.
- * 6. &drm_crtc_helper_funcs.mode_fixup is called last, to fix up the mode with crtc constraints.
+ * 7. &drm_crtc_helper_funcs.mode_fixup is called last, to fix up the mode with crtc constraints.
  *
  * &drm_crtc_state.mode_changed is set when the input mode is changed.
  * &drm_crtc_state.connectors_changed is set when a connector is added or
@@ -617,6 +699,10 @@ static int handle_conflicting_encoders(struct drm_atomic_state *state,
 			return ret;
 	}
 
+	ret = mode_valid(state);
+	if (ret)
+		return ret;
+
 	return mode_fixup(state);
 }
 EXPORT_SYMBOL(drm_atomic_helper_check_modeset);
Signature · 1 line
1.9.1
#6 lore raw

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

In reply to Jose Abreu
Quoted 12 lines · Jose Abreu

This changes the connector probe helper function to use the new encoder->mode_valid() and crtc->mode_valid() helper callbacks to validate the modes.

The new callbacks are optional so the behaviour remains the same if they are not implemented. If they are, then the code loops through all the connector's encodersXcrtcs and calls the callback.

If at least a valid encoderXcrtc combination is found which accepts the mode then the function returns MODE_OK.

Quoted 8 lines
Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>

A few comments below.
-Daniel

Quoted 40 lines
---
 drivers/gpu/drm/drm_probe_helper.c | 71 +++++++++++++++++++++++++++++++++++---
 1 file changed, 67 insertions(+), 4 deletions(-)
drivers/gpu/drm/drm_probe_helper.c +28 -0
index 1b0c14a..bf19f82 100644
@@ -80,6 +80,67 @@
 	return MODE_OK;
 }
 
+static enum drm_mode_status
+drm_mode_validate_connector(struct drm_connector *connector,
+			    struct drm_display_mode *mode)
+{
+	const struct drm_connector_helper_funcs *connector_funcs =
+		connector->helper_private;
+	struct drm_device *dev = connector->dev;
+	uint32_t *ids = connector->encoder_ids;
+	enum drm_mode_status ret = MODE_OK;
+	unsigned int i;
+
+	/* Step 1: Validate against connector */
+	if (connector_funcs && connector_funcs->mode_valid)
+		ret = connector_funcs->mode_valid(connector, mode);
+
+	if (ret != MODE_OK)
+		return ret;
+
+	/* Step 2: Validate against encoders and crtcs */
+	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
+		struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
+		const struct drm_encoder_helper_funcs *encoder_funcs;
+		struct drm_crtc *crtc;
+
+		if (!encoder)
+			continue;
+
+		encoder_funcs = encoder->helper_private;

drivers/gpu/drm/drm_probe_helper.c line 120

Quoted 10 lines
drivers/gpu/drm/drm_probe_helper.c +10 -0
+		if (encoder_funcs && encoder_funcs->mode_valid)
+			ret = encoder_funcs->mode_valid(encoder, mode);
+		else
+			ret = MODE_OK; /* encoder accepts everything */
+
+		/* No point in continuing for crtc check as this encoder will
+		 * not accept the mode anyway. If all encoders reject the mode
+		 * then, at exit, ret will not be MODE_OK. */
+		if (ret != MODE_OK)
+			continue;

I think we should validate encoders against connector->possible_ids here. Might be that not many drivers fill this out correctly, and in case fixing that is much work, perhaps as a follow-up. But would be good to at least help look down that part of uapi a bit more.

This isn't checked within atomic and legacy helpers since we assume that ->best_encoder respectively ->atomic_best_encoder gives us a valid encoder
...

drivers/gpu/drm/drm_probe_helper.c line 126

Quoted 6 lines
drivers/gpu/drm/drm_probe_helper.c +6 -0
+
+		drm_for_each_crtc(crtc, dev) {
+			const struct drm_crtc_helper_funcs *crtc_funcs;
+
+			if (!drm_encoder_crtc_ok(encoder, crtc))
+				continue;

We check this one here already in both atomic and legacy helpers, so all drivers should get this right.

Quoted 21 lines
drivers/gpu/drm/drm_probe_helper.c +17 -0
+
+			crtc_funcs = crtc->helper_private;
+			if (!crtc_funcs || !crtc_funcs->mode_valid)
+				return MODE_OK; /* crtc accepts everything */
+
+			ret = crtc_funcs->mode_valid(crtc, mode);
+			if (ret == MODE_OK)
+				/* If we get to this point there is at least
+				 * one combination of encoder+crtc that works
+				 * for this mode. Lets return now. */
+				return ret;
+		}
+	}
+
+	return ret;
+}
+
 static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
 {
 	struct drm_cmdline_mode *cmdline_mode;

drivers/gpu/drm/drm_probe_helper.c void drm_kms_helper_poll_enable(struct drm_device *dev) · line 350

Quoted 9 lines
drivers/gpu/drm/drm_probe_helper.c +4 -2
@@ -283,8 +344,10 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
  *      (if specified)
  *    - drm_mode_validate_flag() checks the modes against basic connector
  *      capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
- *    - the optional &drm_connector_helper_funcs.mode_valid helper can perform
- *      driver and/or hardware specific checks
+ *    - the optional &drm_connector_helper_funcs.mode_valid,
+ *    	&drm_crtc_helper_funcs.mode_valid and
+ *    	&drm_encoder_helper_funcs.mode_valid helpers can perform driver and/or
+ *    	hardware specific checks

I'd leave 2 bullets for connector->mode_valid (sink specific checks) and everything else (source checks, which are also enforced by the modeset/atomic helpers).

Quoted 18 lines
drivers/gpu/drm/drm_probe_helper.c +2 -2
  *
  * 5. Any mode whose status is not OK is pruned from the connector's modes list,
  *    accompanied by a debug message indicating the reason for the mode's
@@ -428,8 +491,8 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 		if (mode->status == MODE_OK)
 			mode->status = drm_mode_validate_flag(mode, mode_flags);
 
-		if (mode->status == MODE_OK && connector_funcs->mode_valid)
-			mode->status = connector_funcs->mode_valid(connector,
+		if (mode->status == MODE_OK)
+			mode->status = drm_mode_validate_connector(connector,
 								   mode);
 	}
 
Signature · 1 line
1.9.1
Signature · 7 lines
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
[email protected]
https://lists.freedesktop.org/mailman/listinfo/dri-devel
#2 lore raw

Re: [PATCH 1/5] drm: Add crtc/encoder/bridge->mode_valid() callbacks

In reply to Jose Abreu
Quoted 17 lines · Jose Abreu

This adds a new callback to crtc, encoder and bridge helper functions called mode_valid(). This callback shall be implemented if the corresponding component has some sort of restriction in the modes that can be displayed. A NULL callback implicates that the component can display all the modes.

Only the callbacks were implemented to simplify review process, following patches will make use of them.

Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>
Quoted 4 lines
---
 include/drm/drm_bridge.h                 | 20 ++++++++++++++++
 include/drm/drm_modeset_helper_vtables.h | 40 ++++++++++++++++++++++++++++++++
 2 files changed, 60 insertions(+)

I think we should also update the kernel-doc for connector->mode_valid, explaining why it is not called in the atomic check phase, but only at mode probe time: To allow userspace to override the kernel's sink checks, in case of broken EDID with wrong limits from the sink.

Otherwise lgtm.
-Daniel

Quoted 94 lines
include/drm/drm_bridge.h +20 -0
index fdd82fc..00c6c36 100644
@@ -59,6 +59,26 @@ struct drm_bridge_funcs {
 	void (*detach)(struct drm_bridge *bridge);
 
 	/**
+	 * @mode_valid:
+	 *
+	 * This callback is used to check if a specific mode is valid in this
+	 * bridge. This should be implemented if the bridge has some sort of
+	 * restriction in the modes it can display. For example, a given bridge
+	 * may be responsible to set a clock value. If the clock can not
+	 * produce all the values for the available modes then this callback
+	 * can be used to restrict the number of modes to only the ones that
+	 * can be displayed.
+	 *
+	 * This is called at mode probe and at atomic check phase.
+	 *
+	 * RETURNS:
+	 *
+	 * drm_mode_status Enum
+	 */
+	enum drm_mode_status (*mode_valid)(struct drm_bridge *crtc,
+					   const struct drm_display_mode *mode);
+
+	/**
 	 * @mode_fixup:
 	 *
 	 * This callback is used to validate and adjust a mode. The paramater
include/drm/drm_modeset_helper_vtables.h +40 -0
index c01c328..bb04688 100644
@@ -106,6 +106,26 @@ struct drm_crtc_helper_funcs {
 	void (*commit)(struct drm_crtc *crtc);
 
 	/**
+	 * @mode_valid:
+	 *
+	 * This callback is used to check if a specific mode is valid in this
+	 * crtc. This should be implemented if the crtc has some sort of
+	 * restriction in the modes it can display. For example, a given crtc
+	 * may be responsible to set a clock value. If the clock can not
+	 * produce all the values for the available modes then this callback
+	 * can be used to restrict the number of modes to only the ones that
+	 * can be displayed.
+	 *
+	 * This is called at mode probe and at atomic check phase.
+	 *
+	 * RETURNS:
+	 *
+	 * drm_mode_status Enum
+	 */
+	enum drm_mode_status (*mode_valid)(struct drm_crtc *crtc,
+					   const struct drm_display_mode *mode);
+
+	/**
 	 * @mode_fixup:
 	 *
 	 * This callback is used to validate a mode. The parameter mode is the
@@ -457,6 +477,26 @@ struct drm_encoder_helper_funcs {
 	void (*dpms)(struct drm_encoder *encoder, int mode);
 
 	/**
+	 * @mode_valid:
+	 *
+	 * This callback is used to check if a specific mode is valid in this
+	 * encoder. This should be implemented if the encoder has some sort
+	 * of restriction in the modes it can display. For example, a given
+	 * encoder may be responsible to set a clock value. If the clock can
+	 * not produce all the values for the available modes then this callback
+	 * can be used to restrict the number of modes to only the ones that
+	 * can be displayed.
+	 *
+	 * This is called at mode probe and at atomic check phase.
+	 *
+	 * RETURNS:
+	 *
+	 * drm_mode_status Enum
+	 */
+	enum drm_mode_status (*mode_valid)(struct drm_encoder *crtc,
+					   const struct drm_display_mode *mode);
+
+	/**
 	 * @mode_fixup:
 	 *
 	 * This callback is used to validate and adjust a mode. The parameter
Signature · 1 line
1.9.1
Signature · 7 lines
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
[email protected]
https://lists.freedesktop.org/mailman/listinfo/dri-devel
#13 lore raw

Re: [PATCH 4/5] drm: Use mode_valid() in atomic modeset

In reply to Jose Abreu
Quoted 25 lines · Jose Abreu
Quoted 17 lines · Ville Syrjälä

drivers/gpu/drm/drm_atomic_helper.c static int handle_conflicting_encoders(struct drm_atomic_state *state, · line 468

Quoted 13 lines · Jose Abreu
drivers/gpu/drm/drm_atomic_helper.c +13 -0
+					    struct drm_encoder *encoder,
+					    struct drm_crtc *crtc,
+					    struct drm_display_mode *mode)
+{
+	const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
+	const struct drm_connector_helper_funcs *connector_funcs =
+		connector->helper_private;
+	const struct drm_encoder_helper_funcs *encoder_funcs =
+		encoder->helper_private;
+	enum drm_mode_status ret = MODE_OK;
+
+	if (connector_funcs && connector_funcs->mode_valid)
+		ret = connector_funcs->mode_valid(connector, mode);

As I mentioned earlier, this would break i915. We either can't call the connector hook at all here, or we have to make it somehow opt-in if some drivers really want to do it.

Ok. You said you let users exceed the limits, but why doesn't it fail in atomic_check and will fail in mode_valid? I guess I can remove it, but this can lead to lots of confusion, i.e. with this series the mode_valid callbacks for all components are called, if I remove just one call the whole point will fall apart.

Quoted 5 lines

Can we think about something else ? I think making it opt-in is not ideal, if the helper is there then it should be used, but if thats the best solution then shall we add a flag which will call or not *all* the mode_valid callbacks in this stage (drm_device.allow_modevalid_call, ...) ?

This is a general issue, not a driver opt-in. With your new callbacks ideally we'll have:
- all the source checks (clock limits, size limits) are in the crtc/encoder/bridge callbacks
- only the sink limit checks (derived from edid or DP aux) are in the connector callback

Letting userspace overwrite these seems like a reasonable idea that we should support in general I think. See also my comment on patch 1 for the connector's mode_valid kerneldoc.

For arcpgu that might mean that you need to move part of the connector's mode_valid checks into the encoder, but since all the encoder modeset is in there already, that seems like a good cleanup of the drm modeset framework.
-Daniel

Signature · 7 lines
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
[email protected]
https://lists.freedesktop.org/mailman/listinfo/dri-devel
#15 lore raw
In reply to Jose Abreu
Quoted 26 lines · Jose Abreu

This series is a follow up from the discussion at [1]. We start by introducing crtc->mode_valid(), encoder->mode_valid() and bridge->mode_valid() callbacks which will be used in followup patches.

Next, at 2/5 we modify the connector probe helper so that only modes which are supported by a given encoder+crtc combination are probbed.

At 3/5 a helper function is introduced that calls all mode_valid() from a set of bridges.

At 4/5 we call all the mode_valid() callbacks for a given pipeline so that the mode is validated. This is done before calling mode_fixup().

Finally, at 5/5 we use the new crtc->mode_valid() callback in arcpgu and remove the atomic_check() callback.

[1] https://patchwork.kernel.org/patch/9702233/

Jose Abreu (5):
drm: Add crtc/encoder/bridge->mode_valid() callbacks
drm: Use new mode_valid() helpers in connector probe helper
drm: Introduce drm_bridge_mode_valid()
drm: Use mode_valid() in atomic modeset
drm: arc: Use crtc->mode_valid() callback

Quoted 7 lines
Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>

Looks nice. A few small things from Ville and me, but with those addressed this looks all ready for merging and seems like a good improvement to the modeset framework.

Ok, one more patch at the end is needed: We need to review and upate the kernel-doc for all the existing hooks, and add cross-links between mode_valid and atomic_check respectively mode_fixup.

Some more drivers using this would be sweet too, but not a blocker.

Thanks, Daniel

Quoted 13 lines
 drivers/gpu/drm/arc/arcpgu_crtc.c        | 39 ++++++++------
 drivers/gpu/drm/drm_atomic_helper.c      | 92 ++++++++++++++++++++++++++++++--
 drivers/gpu/drm/drm_bridge.c             | 33 ++++++++++++
 drivers/gpu/drm/drm_probe_helper.c       | 71 ++++++++++++++++++++++--
 include/drm/drm_bridge.h                 | 22 ++++++++
 include/drm/drm_modeset_helper_vtables.h | 40 ++++++++++++++
 6 files changed, 275 insertions(+), 22 deletions(-)
Signature · 1 line
1.9.1
Signature · 7 lines
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
[email protected]
https://lists.freedesktop.org/mailman/listinfo/dri-devel
author
#7 lore raw

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

In reply to Daniel Vetter

Hi Daniel,

Quoted 21 lines · Daniel Vetter
Quoted 12 lines · Jose Abreu

This changes the connector probe helper function to use the new encoder->mode_valid() and crtc->mode_valid() helper callbacks to validate the modes.

The new callbacks are optional so the behaviour remains the same if they are not implemented. If they are, then the code loops through all the connector's encodersXcrtcs and calls the callback.

If at least a valid encoderXcrtc combination is found which accepts the mode then the function returns MODE_OK.

Quoted 8 lines
Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>
Quoted 2 lines

A few comments below.
-Daniel

Thanks for the review!

Quoted 47 lines
Quoted 47 lines
---
 drivers/gpu/drm/drm_probe_helper.c | 71 +++++++++++++++++++++++++++++++++++---
 1 file changed, 67 insertions(+), 4 deletions(-)
drivers/gpu/drm/drm_probe_helper.c +34 -0
index 1b0c14a..bf19f82 100644
@@ -80,6 +80,67 @@
 	return MODE_OK;
 }
 
+static enum drm_mode_status
+drm_mode_validate_connector(struct drm_connector *connector,
+			    struct drm_display_mode *mode)
+{
+	const struct drm_connector_helper_funcs *connector_funcs =
+		connector->helper_private;
+	struct drm_device *dev = connector->dev;
+	uint32_t *ids = connector->encoder_ids;
+	enum drm_mode_status ret = MODE_OK;
+	unsigned int i;
+
+	/* Step 1: Validate against connector */
+	if (connector_funcs && connector_funcs->mode_valid)
+		ret = connector_funcs->mode_valid(connector, mode);
+
+	if (ret != MODE_OK)
+		return ret;
+
+	/* Step 2: Validate against encoders and crtcs */
+	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
+		struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
+		const struct drm_encoder_helper_funcs *encoder_funcs;
+		struct drm_crtc *crtc;
+
+		if (!encoder)
+			continue;
+
+		encoder_funcs = encoder->helper_private;
+		if (encoder_funcs && encoder_funcs->mode_valid)
+			ret = encoder_funcs->mode_valid(encoder, mode);
+		else
+			ret = MODE_OK; /* encoder accepts everything */
+
+		/* No point in continuing for crtc check as this encoder will
Quoted 8 lines

drivers/gpu/drm/drm_probe_helper.c line 120

Quoted 4 lines
drivers/gpu/drm/drm_probe_helper.c +4 -0
+		 * not accept the mode anyway. If all encoders reject the mode
+		 * then, at exit, ret will not be MODE_OK. */
+		if (ret != MODE_OK)
+			continue;

I think we should validate encoders against connector->possible_ids here. Might be that not many drivers fill this out correctly, and in case fixing that is much work, perhaps as a follow-up. But would be good to at least help look down that part of uapi a bit more.

I'm sorry but I'm not following you here (I think I need more coffee :)).

What do you mean by connector->possible_ids ? Is this something new ? Because I didn't find anything in my tree and I'm based on today's drm-next from Dave.

Quoted 5 lines

This isn't checked within atomic and legacy helpers since we assume that ->best_encoder respectively ->atomic_best_encoder gives us a valid encoder
...

Quoted 8 lines

drivers/gpu/drm/drm_probe_helper.c line 126

Quoted 6 lines
drivers/gpu/drm/drm_probe_helper.c +6 -0
+
+		drm_for_each_crtc(crtc, dev) {
+			const struct drm_crtc_helper_funcs *crtc_funcs;
+
+			if (!drm_encoder_crtc_ok(encoder, crtc))
+				continue;

We check this one here already in both atomic and legacy helpers, so all drivers should get this right.

But drm_for_each_crtc() iterates over all crtc from a device and some crtcs may only be used by specific encoders (by setting encoder->possible_crtcs), right ? We need to iterate only over the encoder's crtc we want to validate.

Quoted 26 lines
Quoted 26 lines
drivers/gpu/drm/drm_probe_helper.c +17 -1
+
+			crtc_funcs = crtc->helper_private;
+			if (!crtc_funcs || !crtc_funcs->mode_valid)
+				return MODE_OK; /* crtc accepts everything */
+
+			ret = crtc_funcs->mode_valid(crtc, mode);
+			if (ret == MODE_OK)
+				/* If we get to this point there is at least
+				 * one combination of encoder+crtc that works
+				 * for this mode. Lets return now. */
+				return ret;
+		}
+	}
+
+	return ret;
+}
+
 static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
 {
 	struct drm_cmdline_mode *cmdline_mode;
@@ -283,8 +344,10 @@ void drm_kms_helper_poll_enable(struct drm_device *dev)
  *      (if specified)
  *    - drm_mode_validate_flag() checks the modes against basic connector
  *      capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)
- *    - the optional &drm_connector_helper_funcs.mode_valid helper can perform
Quoted 8 lines

drivers/gpu/drm/drm_probe_helper.c void drm_kms_helper_poll_enable(struct drm_device *dev) · line 350

Quoted 5 lines
drivers/gpu/drm/drm_probe_helper.c +4 -1
- *      driver and/or hardware specific checks
+ *    - the optional &drm_connector_helper_funcs.mode_valid,
+ *    	&drm_crtc_helper_funcs.mode_valid and
+ *    	&drm_encoder_helper_funcs.mode_valid helpers can perform driver and/or
+ *    	hardware specific checks

I'd leave 2 bullets for connector->mode_valid (sink specific checks) and everything else (source checks, which are also enforced by the modeset/atomic helpers).

Ok, thanks!

Best regards,
Jose Miguel Abreu

Quoted 18 lines
Quoted 18 lines
drivers/gpu/drm/drm_probe_helper.c +2 -2
  *
  * 5. Any mode whose status is not OK is pruned from the connector's modes list,
  *    accompanied by a debug message indicating the reason for the mode's
@@ -428,8 +491,8 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 		if (mode->status == MODE_OK)
 			mode->status = drm_mode_validate_flag(mode, mode_flags);
 
-		if (mode->status == MODE_OK && connector_funcs->mode_valid)
-			mode->status = connector_funcs->mode_valid(connector,
+		if (mode->status == MODE_OK)
+			mode->status = drm_mode_validate_connector(connector,
 								   mode);
 	}
 
Signature · 1 line
1.9.1
#8 lore raw

Re: [PATCH 2/5] drm: Use new mode_valid() helpers in connector probe helper

Quoted 86 lines · Jose Abreu

Hi Daniel,

Quoted 21 lines · Daniel Vetter
Quoted 12 lines · Jose Abreu

This changes the connector probe helper function to use the new encoder->mode_valid() and crtc->mode_valid() helper callbacks to validate the modes.

The new callbacks are optional so the behaviour remains the same if they are not implemented. If they are, then the code loops through all the connector's encodersXcrtcs and calls the callback.

If at least a valid encoderXcrtc combination is found which accepts the mode then the function returns MODE_OK.

Quoted 8 lines
Cc Carlos Palminha <[email protected]>
Cc Alexey Brodkin <[email protected]>
Cc Ville Syrjälä <[email protected]>
Cc Daniel Vetter <[email protected]>
Cc Dave Airlie <[email protected]>
Cc Andrzej Hajda <[email protected]>
Cc Archit Taneja <[email protected]>
Quoted 2 lines

A few comments below.
-Daniel

Thanks for the review!

Quoted 47 lines
Quoted 47 lines
---
 drivers/gpu/drm/drm_probe_helper.c | 71 +++++++++++++++++++++++++++++++++++---
 1 file changed, 67 insertions(+), 4 deletions(-)
drivers/gpu/drm/drm_probe_helper.c +34 -0
index 1b0c14a..bf19f82 100644
@@ -80,6 +80,67 @@
 	return MODE_OK;
 }
 
+static enum drm_mode_status
+drm_mode_validate_connector(struct drm_connector *connector,
+			    struct drm_display_mode *mode)
+{
+	const struct drm_connector_helper_funcs *connector_funcs =
+		connector->helper_private;
+	struct drm_device *dev = connector->dev;
+	uint32_t *ids = connector->encoder_ids;
+	enum drm_mode_status ret = MODE_OK;
+	unsigned int i;
+
+	/* Step 1: Validate against connector */
+	if (connector_funcs && connector_funcs->mode_valid)
+		ret = connector_funcs->mode_valid(connector, mode);
+
+	if (ret != MODE_OK)
+		return ret;
+
+	/* Step 2: Validate against encoders and crtcs */
+	for (i = 0; i < DRM_CONNECTOR_MAX_ENCODER; i++) {
+		struct drm_encoder *encoder = drm_encoder_find(dev, ids[i]);
+		const struct drm_encoder_helper_funcs *encoder_funcs;
+		struct drm_crtc *crtc;
+
+		if (!encoder)
+			continue;
+
+		encoder_funcs = encoder->helper_private;
+		if (encoder_funcs && encoder_funcs->mode_valid)
+			ret = encoder_funcs->mode_valid(encoder, mode);
+		else
+			ret = MODE_OK; /* encoder accepts everything */
+
+		/* No point in continuing for crtc check as this encoder will
Quoted 8 lines

drivers/gpu/drm/drm_probe_helper.c line 120

Quoted 4 lines
drivers/gpu/drm/drm_probe_helper.c +4 -0
+		 * not accept the mode anyway. If all encoders reject the mode
+		 * then, at exit, ret will not be MODE_OK. */
+		if (ret != MODE_OK)
+			continue;

I think we should validate encoders against connector->possible_ids here. Might be that not many drivers fill this out correctly, and in case fixing that is much work, perhaps as a follow-up. But would be good to at least help look down that part of uapi a bit more.

Quoted 6 lines

I'm sorry but I'm not following you here (I think I need more coffee :)).

What do you mean by connector->possible_ids ? Is this something new ? Because I didn't find anything in my tree and I'm based on today's drm-next from Dave.

Oops, I guess I was on an old tree or whatever by accident. I meant drm_connector->encoder_ids, that limits the encoders you can use on a crtc. For many drivers there's only one.

Quoted 13 lines
Quoted 4 lines

This isn't checked within atomic and legacy helpers since we assume that ->best_encoder respectively ->atomic_best_encoder gives us a valid encoder
...

Quoted 8 lines

drivers/gpu/drm/drm_probe_helper.c line 126

Quoted 6 lines
drivers/gpu/drm/drm_probe_helper.c +6 -0
+
+		drm_for_each_crtc(crtc, dev) {
+			const struct drm_crtc_helper_funcs *crtc_funcs;
+
+			if (!drm_encoder_crtc_ok(encoder, crtc))
+				continue;

We check this one here already in both atomic and legacy helpers, so all drivers should get this right.

Quoted 4 lines

But drm_for_each_crtc() iterates over all crtc from a device and some crtcs may only be used by specific encoders (by setting encoder->possible_crtcs), right ? We need to iterate only over the encoder's crtc we want to validate.

This was a comment about ->encoder_ids, since we don't validate that in the atomic helpers (but instead rely on ->(atomic_)best_encoder to give us the right encoder) validating here in this function might be a problem and uncover driver bugs. But for drm_encoder_crtc_ok there's no such risk, so this is safe.

I was simply dumping my thoughts while reviewing, the code is all good :-)

Cheers, Daniel

Signature · 7 lines
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
[email protected]
https://lists.freedesktop.org/mailman/listinfo/dri-devel