drm/i915/dp: link rate and lane count refactoring

I can't think of a real world bug this could cause now, but this will be required in follow-up work. While at it, change the parameter order to be slightly more sensible.

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +6 -5

index fd96a6cf7326..88c708b07c70 100644
@@ -1538,12 +1538,12 @@ bool intel_dp_read_desc(struct intel_dp *intel_dp)
 	return true;
 }
 
-static int rate_to_index(int find, const int *rates)
+static int rate_to_index(const int *rates, int len, int rate)
 {
-	int i = 0;
+	int i;
 
-	for (i = 0; i < DP_MAX_SUPPORTED_RATES; ++i)
-		if (find == rates[i])
+	for (i = 0; i < len; i++)
+		if (rate == rates[i])
 			break;
 
 	return i;

@@ -1564,7 +1564,8 @@ intel_dp_max_link_rate(struct intel_dp *intel_dp)
 
 int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)
 {
-	return rate_to_index(rate, intel_dp->sink_rates);
+	return rate_to_index(intel_dp->sink_rates, intel_dp->num_sink_rates,
+			     rate);
 }
 
 void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,

Signature · 1 line

2.1.4

We shouldn't silently use the first element if we can't find the rate we're looking for. Make rate_to_index() more generally useful, and fallback to the first element in the caller, with a big warning.

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +9 -4

index 88c708b07c70..0e200a37b75b 100644
@@ -1544,9 +1544,9 @@ static int rate_to_index(const int *rates, int len, int rate)
 
 	for (i = 0; i < len; i++)
 		if (rate == rates[i])
-			break;
+			return i;
 
-	return i;
+	return -1;
 }
 
 int

@@ -1564,8 +1564,13 @@ intel_dp_max_link_rate(struct intel_dp *intel_dp)
 
 int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)
 {
-	return rate_to_index(intel_dp->sink_rates, intel_dp->num_sink_rates,
-			     rate);
+	int i = rate_to_index(intel_dp->sink_rates, intel_dp->num_sink_rates,
+			      rate);
+
+	if (WARN_ON(i < 0))
+		i = 0;
+
+	return i;
 }
 
 void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,

Signature · 1 line

2.1.4

Won't it make more sense to squash this patch with Patch 01 in this series? When i was reading Patch 1, I almost was going to comment about handling the case where we dont find the index..

Regards
Manasi

Quoted 46 lines · Jani Nikula

We shouldn't silently use the first element if we can't find the rate we're looking for. Make rate_to_index() more generally useful, and fallback to the first element in the caller, with a big warning.

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +9 -4

index 88c708b07c70..0e200a37b75b 100644
@@ -1544,9 +1544,9 @@ static int rate_to_index(const int *rates, int len, int rate)
 
 	for (i = 0; i < len; i++)
 		if (rate == rates[i])
-			break;
+			return i;
 
-	return i;
+	return -1;
 }
 
 int

@@ -1564,8 +1564,13 @@ intel_dp_max_link_rate(struct intel_dp *intel_dp)
 
 int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)
 {
-	return rate_to_index(intel_dp->sink_rates, intel_dp->num_sink_rates,
-			     rate);
+	int i = rate_to_index(intel_dp->sink_rates, intel_dp->num_sink_rates,
+			      rate);
+
+	if (WARN_ON(i < 0))
+		i = 0;
+
+	return i;
 }
 
 void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,

Signature · 1 line

2.1.4

Quoted 3 lines · Manasi Navare

Won't it make more sense to squash this patch with Patch 01 in this series? When i was reading Patch 1, I almost was going to comment about handling the case where we dont find the index..

Matter of taste. You might then look at patch 3 and figure it should be squashed too... you have to draw the line somewhere, and I think it's always easier to review smaller pieces and be sure they are each correct. If you find an issue with the 2nd patch, the 1st one is still valid, and the follow-up review is also easier.

BR,
Jani.

Quoted 5 lines

Regards
Manasi

Quoted 8 lines · Jani Nikula

Quoted 7 lines

We shouldn't silently use the first element if we can't find the rate we're looking for. Make rate_to_index() more generally useful, and fallback to the first element in the caller, with a big warning.

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

Quoted 35 lines

Quoted 35 lines

---
 drivers/gpu/drm/i915/intel_dp.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +9 -4

index 88c708b07c70..0e200a37b75b 100644
@@ -1544,9 +1544,9 @@ static int rate_to_index(const int *rates, int len, int rate)
 
 	for (i = 0; i < len; i++)
 		if (rate == rates[i])
-			break;
+			return i;
 
-	return i;
+	return -1;
 }
 
 int

@@ -1564,8 +1564,13 @@ intel_dp_max_link_rate(struct intel_dp *intel_dp)
 
 int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)
 {
-	return rate_to_index(intel_dp->sink_rates, intel_dp->num_sink_rates,
-			     rate);
+	int i = rate_to_index(intel_dp->sink_rates, intel_dp->num_sink_rates,
+			      rate);
+
+	if (WARN_ON(i < 0))
+		i = 0;
+
+	return i;
 }
 

Quoted 4 lines

Quoted 4 lines

drivers/gpu/drm/i915/intel_dp.c +0 -0

 void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,

Signature · 1 line

2.1.4

Signature · 1 line

Jani Nikula, Intel Open Source Technology Center

Rename the function, move it at the top, and reuse in intel_dp_link_rate_index(). If there was a reason in the past to use reverse search order here, there isn't now.

The names may be slightly confusing now, but intel_dp_link_rate_index() will go away in follow-up patches.

v2: Use name intel_dp_rate_index (Dhinakaran)

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c | 34 +++++++++++++++-------------------
 1 file changed, 15 insertions(+), 19 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +15 -19

index 0e200a37b75b..9fc066dda4e0 100644
@@ -266,6 +266,18 @@ static int intersect_rates(const int *source_rates, int source_len,
 	return k;
 }
 
+/* return index of rate in rates array, or -1 if not found */
+static int intel_dp_rate_index(const int *rates, int len, int rate)
+{
+	int i;
+
+	for (i = 0; i < len; i++)
+		if (rate == rates[i])
+			return i;
+
+	return -1;
+}
+
 static int intel_dp_common_rates(struct intel_dp *intel_dp,
 				 int *common_rates)
 {

@@ -284,15 +296,10 @@ static int intel_dp_link_rate_index(struct intel_dp *intel_dp,
 				    int *common_rates, int link_rate)
 {
 	int common_len;
-	int index;
 
 	common_len = intel_dp_common_rates(intel_dp, common_rates);
-	for (index = 0; index < common_len; index++) {
-		if (link_rate == common_rates[common_len - index - 1])
-			return common_len - index - 1;
-	}
 
-	return -1;
+	return intel_dp_rate_index(common_rates, common_len, link_rate);
 }
 
 int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,

@@ -1538,17 +1545,6 @@ bool intel_dp_read_desc(struct intel_dp *intel_dp)
 	return true;
 }
 
-static int rate_to_index(const int *rates, int len, int rate)
-{
-	int i;
-
-	for (i = 0; i < len; i++)
-		if (rate == rates[i])
-			return i;
-
-	return -1;
-}
-
 int
 intel_dp_max_link_rate(struct intel_dp *intel_dp)
 {

@@ -1564,8 +1560,8 @@ intel_dp_max_link_rate(struct intel_dp *intel_dp)
 
 int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)
 {
-	int i = rate_to_index(intel_dp->sink_rates, intel_dp->num_sink_rates,
-			      rate);
+	int i = intel_dp_rate_index(intel_dp->sink_rates,
+				    intel_dp->num_sink_rates, rate);
 
 	if (WARN_ON(i < 0))
 		i = 0;

Signature · 1 line

2.1.4

We need the source rates array so often that it makes sense to set it once at init. This reduces function calls when we need the rates, making the code easier to follow.

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c  | 35 +++++++++++++++++++++--------------
 drivers/gpu/drm/i915/intel_drv.h |  3 +++
 2 files changed, 24 insertions(+), 14 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +21 -14

index 9fc066dda4e0..e9bd75ff3904 100644
@@ -218,21 +218,25 @@ intel_dp_sink_rates(struct intel_dp *intel_dp, const int **sink_rates)
 	return (intel_dp->max_sink_link_bw >> 3) + 1;
 }
 
-static int
-intel_dp_source_rates(struct intel_dp *intel_dp, const int **source_rates)
+static void
+intel_dp_set_source_rates(struct intel_dp *intel_dp)
 {
 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
 	struct drm_i915_private *dev_priv = to_i915(dig_port->base.base.dev);
+	const int *source_rates;
 	int size;
 
+	/* This should only be done once */
+	WARN_ON(intel_dp->source_rates || intel_dp->num_source_rates);
+
 	if (IS_GEN9_LP(dev_priv)) {
-		*source_rates = bxt_rates;
+		source_rates = bxt_rates;
 		size = ARRAY_SIZE(bxt_rates);
 	} else if (IS_GEN9_BC(dev_priv)) {
-		*source_rates = skl_rates;
+		source_rates = skl_rates;
 		size = ARRAY_SIZE(skl_rates);
 	} else {
-		*source_rates = default_rates;
+		source_rates = default_rates;
 		size = ARRAY_SIZE(default_rates);
 	}
 

@@ -240,7 +244,8 @@ intel_dp_source_rates(struct intel_dp *intel_dp, const int **source_rates)
 	if (!intel_dp_source_supports_hbr2(intel_dp))
 		size--;
 
-	return size;
+	intel_dp->source_rates = source_rates;
+	intel_dp->num_source_rates = size;
 }
 
 static int intersect_rates(const int *source_rates, int source_len,

@@ -281,13 +286,13 @@ static int intel_dp_rate_index(const int *rates, int len, int rate)
 static int intel_dp_common_rates(struct intel_dp *intel_dp,
 				 int *common_rates)
 {
-	const int *source_rates, *sink_rates;
-	int source_len, sink_len;
+	const int *sink_rates;
+	int sink_len;
 
 	sink_len = intel_dp_sink_rates(intel_dp, &sink_rates);
-	source_len = intel_dp_source_rates(intel_dp, &source_rates);
 
-	return intersect_rates(source_rates, source_len,
+	return intersect_rates(intel_dp->source_rates,
+			       intel_dp->num_source_rates,
 			       sink_rates, sink_len,
 			       common_rates);
 }

@@ -1493,16 +1498,16 @@ static void snprintf_int_array(char *str, size_t len,
 
 static void intel_dp_print_rates(struct intel_dp *intel_dp)
 {
-	const int *source_rates, *sink_rates;
-	int source_len, sink_len, common_len;
+	const int *sink_rates;
+	int sink_len, common_len;
 	int common_rates[DP_MAX_SUPPORTED_RATES];
 	char str[128]; /* FIXME: too big for stack? */
 
 	if ((drm_debug & DRM_UT_KMS) == 0)
 		return;
 
-	source_len = intel_dp_source_rates(intel_dp, &source_rates);
-	snprintf_int_array(str, sizeof(str), source_rates, source_len);
+	snprintf_int_array(str, sizeof(str),
+			   intel_dp->source_rates, intel_dp->num_source_rates);
 	DRM_DEBUG_KMS("source rates: %s\n", str);
 
 	sink_len = intel_dp_sink_rates(intel_dp, &sink_rates);

@@ -5943,6 +5948,8 @@ intel_dp_init_connector(struct intel_digital_port *intel_dig_port,
 		 intel_dig_port->max_lanes, port_name(port)))
 		return false;
 
+	intel_dp_set_source_rates(intel_dp);
+
 	intel_dp->reset_link_params = true;
 	intel_dp->pps_pipe = INVALID_PIPE;
 	intel_dp->active_pipe = INVALID_PIPE;

drivers/gpu/drm/i915/intel_drv.h +3 -0

index e24641b559e2..f59574261dc6 100644
@@ -949,6 +949,9 @@ struct intel_dp {
 	uint8_t psr_dpcd[EDP_PSR_RECEIVER_CAP_SIZE];
 	uint8_t downstream_ports[DP_MAX_DOWNSTREAM_PORTS];
 	uint8_t edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];
+	/* source rates */
+	int num_source_rates;
+	const int *source_rates;
 	/* sink rates as reported by DP_SUPPORTED_LINK_RATES */
 	uint8_t num_sink_rates;
 	int sink_rates[DP_MAX_SUPPORTED_RATES];

Signature · 1 line

2.1.4

There is some conflation related to sink rates, making this change more complicated than it would otherwise have to be. There are three changes here that are rather difficult to split up:

1) Use the intel_dp->sink_rates array for all DP, not just eDP 1.4. We initialize it from DPCD on eDP 1.4 like before, but generate it based on DP_MAX_LINK_RATE on others. This reduces code complexity when we need to use the sink rates; they are all always in the sink_rates array.

2) Update the sink rate array whenever we read DPCD, and use the information from there. This increases code readability when we need the sink rates.

3) Disentangle fallback rate limiting from sink rates. In the code, the max rate is a dynamic property of the *link*, not of the *sink*. Do the limiting after intersecting the source and sink rates, which are static properties of the devices.

This paves the way for follow-up refactoring that I've refrained from doing here to keep this change as simple as it possibly can.

v2: introduce use_rate_select and handle non-confirming eDP (Ville)

v3: don't clobber cached eDP rates on short pulse (Ville)

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c               | 81 ++++++++++++++++++---------
 drivers/gpu/drm/i915/intel_dp_link_training.c |  3 +-
 drivers/gpu/drm/i915/intel_drv.h              |  5 +-
 3 files changed, 61 insertions(+), 28 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +56 -25

index e9bd75ff3904..b38cba7d5abc 100644
@@ -133,6 +133,34 @@ static void vlv_steal_power_sequencer(struct drm_device *dev,
 				      enum pipe pipe);
 static void intel_dp_unset_edid(struct intel_dp *intel_dp);
 
+static int intel_dp_num_rates(u8 link_bw_code)
+{
+	switch (link_bw_code) {
+	default:
+		WARN(1, "invalid max DP link bw val %x, using 1.62Gbps\n",
+		     link_bw_code);
+	case DP_LINK_BW_1_62:
+		return 1;
+	case DP_LINK_BW_2_7:
+		return 2;
+	case DP_LINK_BW_5_4:
+		return 3;
+	}
+}
+
+/* update sink rates from dpcd */
+static void intel_dp_set_sink_rates(struct intel_dp *intel_dp)
+{
+	int i, num_rates;
+
+	num_rates = intel_dp_num_rates(intel_dp->dpcd[DP_MAX_LINK_RATE]);
+
+	for (i = 0; i < num_rates; i++)
+		intel_dp->sink_rates[i] = default_rates[i];
+
+	intel_dp->num_sink_rates = num_rates;
+}
+
 static int
 intel_dp_max_link_bw(struct intel_dp  *intel_dp)
 {

@@ -205,19 +233,6 @@ intel_dp_downstream_max_dotclock(struct intel_dp *intel_dp)
 	return max_dotclk;
 }
 
-static int
-intel_dp_sink_rates(struct intel_dp *intel_dp, const int **sink_rates)
-{
-	if (intel_dp->num_sink_rates) {
-		*sink_rates = intel_dp->sink_rates;
-		return intel_dp->num_sink_rates;
-	}
-
-	*sink_rates = default_rates;
-
-	return (intel_dp->max_sink_link_bw >> 3) + 1;
-}
-
 static void
 intel_dp_set_source_rates(struct intel_dp *intel_dp)
 {

@@ -286,15 +301,22 @@ static int intel_dp_rate_index(const int *rates, int len, int rate)
 static int intel_dp_common_rates(struct intel_dp *intel_dp,
 				 int *common_rates)
 {
-	const int *sink_rates;
-	int sink_len;
+	int max_rate = drm_dp_bw_code_to_link_rate(intel_dp->max_sink_link_bw);
+	int i, common_len;
 
-	sink_len = intel_dp_sink_rates(intel_dp, &sink_rates);
+	common_len = intersect_rates(intel_dp->source_rates,
+				     intel_dp->num_source_rates,
+				     intel_dp->sink_rates,
+				     intel_dp->num_sink_rates,
+				     common_rates);
+
+	/* Limit results by potentially reduced max rate */
+	for (i = 0; i < common_len; i++) {
+		if (common_rates[common_len - i - 1] <= max_rate)
+			return common_len - i;
+	}
 
-	return intersect_rates(intel_dp->source_rates,
-			       intel_dp->num_source_rates,
-			       sink_rates, sink_len,
-			       common_rates);
+	return 0;
 }
 
 static int intel_dp_link_rate_index(struct intel_dp *intel_dp,

@@ -1498,8 +1520,7 @@ static void snprintf_int_array(char *str, size_t len,
 
 static void intel_dp_print_rates(struct intel_dp *intel_dp)
 {
-	const int *sink_rates;
-	int sink_len, common_len;
+	int common_len;
 	int common_rates[DP_MAX_SUPPORTED_RATES];
 	char str[128]; /* FIXME: too big for stack? */
 

@@ -1510,8 +1531,8 @@ static void intel_dp_print_rates(struct intel_dp *intel_dp)
 			   intel_dp->source_rates, intel_dp->num_source_rates);
 	DRM_DEBUG_KMS("source rates: %s\n", str);
 
-	sink_len = intel_dp_sink_rates(intel_dp, &sink_rates);
-	snprintf_int_array(str, sizeof(str), sink_rates, sink_len);
+	snprintf_int_array(str, sizeof(str),
+			   intel_dp->sink_rates, intel_dp->num_sink_rates);
 	DRM_DEBUG_KMS("sink rates: %s\n", str);
 
 	common_len = intel_dp_common_rates(intel_dp, common_rates);

@@ -1577,7 +1598,8 @@ int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)
 void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,
 			   uint8_t *link_bw, uint8_t *rate_select)
 {
-	if (intel_dp->num_sink_rates) {
+	/* eDP 1.4 rate select method. */
+	if (intel_dp->use_rate_select) {
 		*link_bw = 0;
 		*rate_select =
 			intel_dp_rate_select(intel_dp, port_clock);

@@ -3702,6 +3724,11 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp)
 		intel_dp->num_sink_rates = i;
 	}
 
+	if (intel_dp->num_sink_rates)
+		intel_dp->use_rate_select = true;
+	else
+		intel_dp_set_sink_rates(intel_dp);
+
 	return true;
 }
 

@@ -3712,6 +3739,10 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
 	if (!intel_dp_read_dpcd(intel_dp))
 		return false;
 
+	/* Don't clobber cached eDP rates. */
+	if (!is_edp(intel_dp))
+		intel_dp_set_sink_rates(intel_dp);
+
 	if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT,
 			     &intel_dp->sink_count, 1) < 0)
 		return false;

drivers/gpu/drm/i915/intel_dp_link_training.c +2 -1

index 0048b520baf7..694ad0ffb523 100644
@@ -146,7 +146,8 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
 		link_config[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
 	drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_BW_SET, link_config, 2);
 
-	if (intel_dp->num_sink_rates)
+	/* eDP 1.4 rate select method. */
+	if (!link_bw)
 		drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_RATE_SET,
 				  &rate_select, 1);
 

drivers/gpu/drm/i915/intel_drv.h +3 -2

index f59574261dc6..77a94aaa98c2 100644
@@ -952,9 +952,10 @@ struct intel_dp {
 	/* source rates */
 	int num_source_rates;
 	const int *source_rates;
-	/* sink rates as reported by DP_SUPPORTED_LINK_RATES */
-	uint8_t num_sink_rates;
+	/* sink rates as reported by DP_MAX_LINK_RATE/DP_SUPPORTED_LINK_RATES */
+	int num_sink_rates;
 	int sink_rates[DP_MAX_SUPPORTED_RATES];
+	bool use_rate_select;
 	/* Max lane count for the sink as per DPCD registers */
 	uint8_t max_sink_lane_count;
 	/* Max link BW for the sink as per DPCD registers */

Signature · 1 line

2.1.4

I agree with disentangling the fallback rate limiting from sink rates and instead just limiting the common_rates array based on max link rate.

Reviewed-by <[email protected]>

Manasi

Quoted 212 lines · Jani Nikula

There is some conflation related to sink rates, making this change more complicated than it would otherwise have to be. There are three changes here that are rather difficult to split up:

1) Use the intel_dp->sink_rates array for all DP, not just eDP 1.4. We initialize it from DPCD on eDP 1.4 like before, but generate it based on DP_MAX_LINK_RATE on others. This reduces code complexity when we need to use the sink rates; they are all always in the sink_rates array.

2) Update the sink rate array whenever we read DPCD, and use the information from there. This increases code readability when we need the sink rates.

3) Disentangle fallback rate limiting from sink rates. In the code, the max rate is a dynamic property of the *link*, not of the *sink*. Do the limiting after intersecting the source and sink rates, which are static properties of the devices.

This paves the way for follow-up refactoring that I've refrained from doing here to keep this change as simple as it possibly can.

v2: introduce use_rate_select and handle non-confirming eDP (Ville)

v3: don't clobber cached eDP rates on short pulse (Ville)

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c               | 81 ++++++++++++++++++---------
 drivers/gpu/drm/i915/intel_dp_link_training.c |  3 +-
 drivers/gpu/drm/i915/intel_drv.h              |  5 +-
 3 files changed, 61 insertions(+), 28 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +56 -25

index e9bd75ff3904..b38cba7d5abc 100644
@@ -133,6 +133,34 @@ static void vlv_steal_power_sequencer(struct drm_device *dev,
 				      enum pipe pipe);
 static void intel_dp_unset_edid(struct intel_dp *intel_dp);
 
+static int intel_dp_num_rates(u8 link_bw_code)
+{
+	switch (link_bw_code) {
+	default:
+		WARN(1, "invalid max DP link bw val %x, using 1.62Gbps\n",
+		     link_bw_code);
+	case DP_LINK_BW_1_62:
+		return 1;
+	case DP_LINK_BW_2_7:
+		return 2;
+	case DP_LINK_BW_5_4:
+		return 3;
+	}
+}
+
+/* update sink rates from dpcd */
+static void intel_dp_set_sink_rates(struct intel_dp *intel_dp)
+{
+	int i, num_rates;
+
+	num_rates = intel_dp_num_rates(intel_dp->dpcd[DP_MAX_LINK_RATE]);
+
+	for (i = 0; i < num_rates; i++)
+		intel_dp->sink_rates[i] = default_rates[i];
+
+	intel_dp->num_sink_rates = num_rates;
+}
+
 static int
 intel_dp_max_link_bw(struct intel_dp  *intel_dp)
 {

@@ -205,19 +233,6 @@ intel_dp_downstream_max_dotclock(struct intel_dp *intel_dp)
 	return max_dotclk;
 }
 
-static int
-intel_dp_sink_rates(struct intel_dp *intel_dp, const int **sink_rates)
-{
-	if (intel_dp->num_sink_rates) {
-		*sink_rates = intel_dp->sink_rates;
-		return intel_dp->num_sink_rates;
-	}
-
-	*sink_rates = default_rates;
-
-	return (intel_dp->max_sink_link_bw >> 3) + 1;
-}
-
 static void
 intel_dp_set_source_rates(struct intel_dp *intel_dp)
 {

@@ -286,15 +301,22 @@ static int intel_dp_rate_index(const int *rates, int len, int rate)
 static int intel_dp_common_rates(struct intel_dp *intel_dp,
 				 int *common_rates)
 {
-	const int *sink_rates;
-	int sink_len;
+	int max_rate = drm_dp_bw_code_to_link_rate(intel_dp->max_sink_link_bw);
+	int i, common_len;
 
-	sink_len = intel_dp_sink_rates(intel_dp, &sink_rates);
+	common_len = intersect_rates(intel_dp->source_rates,
+				     intel_dp->num_source_rates,
+				     intel_dp->sink_rates,
+				     intel_dp->num_sink_rates,
+				     common_rates);
+
+	/* Limit results by potentially reduced max rate */
+	for (i = 0; i < common_len; i++) {
+		if (common_rates[common_len - i - 1] <= max_rate)
+			return common_len - i;
+	}
 
-	return intersect_rates(intel_dp->source_rates,
-			       intel_dp->num_source_rates,
-			       sink_rates, sink_len,
-			       common_rates);
+	return 0;
 }
 
 static int intel_dp_link_rate_index(struct intel_dp *intel_dp,

@@ -1498,8 +1520,7 @@ static void snprintf_int_array(char *str, size_t len,
 
 static void intel_dp_print_rates(struct intel_dp *intel_dp)
 {
-	const int *sink_rates;
-	int sink_len, common_len;
+	int common_len;
 	int common_rates[DP_MAX_SUPPORTED_RATES];
 	char str[128]; /* FIXME: too big for stack? */
 

@@ -1510,8 +1531,8 @@ static void intel_dp_print_rates(struct intel_dp *intel_dp)
 			   intel_dp->source_rates, intel_dp->num_source_rates);
 	DRM_DEBUG_KMS("source rates: %s\n", str);
 
-	sink_len = intel_dp_sink_rates(intel_dp, &sink_rates);
-	snprintf_int_array(str, sizeof(str), sink_rates, sink_len);
+	snprintf_int_array(str, sizeof(str),
+			   intel_dp->sink_rates, intel_dp->num_sink_rates);
 	DRM_DEBUG_KMS("sink rates: %s\n", str);
 
 	common_len = intel_dp_common_rates(intel_dp, common_rates);

@@ -1577,7 +1598,8 @@ int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)
 void intel_dp_compute_rate(struct intel_dp *intel_dp, int port_clock,
 			   uint8_t *link_bw, uint8_t *rate_select)
 {
-	if (intel_dp->num_sink_rates) {
+	/* eDP 1.4 rate select method. */
+	if (intel_dp->use_rate_select) {
 		*link_bw = 0;
 		*rate_select =
 			intel_dp_rate_select(intel_dp, port_clock);

@@ -3702,6 +3724,11 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp)
 		intel_dp->num_sink_rates = i;
 	}
 
+	if (intel_dp->num_sink_rates)
+		intel_dp->use_rate_select = true;
+	else
+		intel_dp_set_sink_rates(intel_dp);
+
 	return true;
 }
 

@@ -3712,6 +3739,10 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
 	if (!intel_dp_read_dpcd(intel_dp))
 		return false;
 
+	/* Don't clobber cached eDP rates. */
+	if (!is_edp(intel_dp))
+		intel_dp_set_sink_rates(intel_dp);
+
 	if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT,
 			     &intel_dp->sink_count, 1) < 0)
 		return false;

drivers/gpu/drm/i915/intel_dp_link_training.c +2 -1

index 0048b520baf7..694ad0ffb523 100644
@@ -146,7 +146,8 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
 		link_config[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
 	drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_BW_SET, link_config, 2);
 
-	if (intel_dp->num_sink_rates)
+	/* eDP 1.4 rate select method. */
+	if (!link_bw)
 		drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_RATE_SET,
 				  &rate_select, 1);
 

drivers/gpu/drm/i915/intel_drv.h +3 -2

index f59574261dc6..77a94aaa98c2 100644
@@ -952,9 +952,10 @@ struct intel_dp {
 	/* source rates */
 	int num_source_rates;
 	const int *source_rates;
-	/* sink rates as reported by DP_SUPPORTED_LINK_RATES */
-	uint8_t num_sink_rates;
+	/* sink rates as reported by DP_MAX_LINK_RATE/DP_SUPPORTED_LINK_RATES */
+	int num_sink_rates;
 	int sink_rates[DP_MAX_SUPPORTED_RATES];
+	bool use_rate_select;
 	/* Max lane count for the sink as per DPCD registers */
 	uint8_t max_sink_lane_count;
 	/* Max link BW for the sink as per DPCD registers */

Signature · 1 line

2.1.4

Now that source rates are static and sink rates are updated whenever DPCD is updated, we can do and cache the intersection of them whenever sink rates are updated. This reduces code complexity, as we don't have to keep calling the functions to intersect. We also get rid of several common rates arrays on stack.

Limiting the common rates by a max link rate can be done by picking the first N elements of the cached common rates.

v2: get rid of the local common_rates variable (Manasi)
v3: don't clobber cached eDP rates on short pulse (Ville)

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c  | 75 ++++++++++++++++++++++------------------
 drivers/gpu/drm/i915/intel_drv.h |  3 ++
 2 files changed, 45 insertions(+), 33 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +42 -33

index e4650f1625cc..1808af6d635d 100644
@@ -284,17 +284,29 @@ static int intel_dp_rate_index(const int *rates, int len, int rate)
 	return -1;
 }
 
-static int intel_dp_common_rates(struct intel_dp *intel_dp,
-				 int *common_rates)
+static void intel_dp_set_common_rates(struct intel_dp *intel_dp)
 {
-	int max_rate = intel_dp->max_sink_link_rate;
-	int i, common_len;
+	WARN_ON(!intel_dp->num_source_rates || !intel_dp->num_sink_rates);
 
-	common_len = intersect_rates(intel_dp->source_rates,
-				     intel_dp->num_source_rates,
-				     intel_dp->sink_rates,
-				     intel_dp->num_sink_rates,
-				     common_rates);
+	intel_dp->num_common_rates = intersect_rates(intel_dp->source_rates,
+						     intel_dp->num_source_rates,
+						     intel_dp->sink_rates,
+						     intel_dp->num_sink_rates,
+						     intel_dp->common_rates);
+
+	/* Paranoia, there should always be something in common. */
+	if (WARN_ON(intel_dp->num_common_rates == 0)) {
+		intel_dp->common_rates[0] = default_rates[0];
+		intel_dp->num_common_rates = 1;
+	}
+}
+
+/* get length of common rates potentially limited by max_rate */
+static int intel_dp_common_len_rate_limit(struct intel_dp *intel_dp,
+					  int max_rate)
+{
+	const int *common_rates = intel_dp->common_rates;
+	int i, common_len = intel_dp->num_common_rates;
 
 	/* Limit results by potentially reduced max rate */
 	for (i = 0; i < common_len; i++) {

@@ -305,25 +317,23 @@ static int intel_dp_common_rates(struct intel_dp *intel_dp,
 	return 0;
 }
 
-static int intel_dp_link_rate_index(struct intel_dp *intel_dp,
-				    int *common_rates, int link_rate)
+static int intel_dp_link_rate_index(struct intel_dp *intel_dp, int link_rate)
 {
 	int common_len;
 
-	common_len = intel_dp_common_rates(intel_dp, common_rates);
+	common_len = intel_dp_common_len_rate_limit(intel_dp,
+						    intel_dp->max_sink_link_rate);
 
-	return intel_dp_rate_index(common_rates, common_len, link_rate);
+	return intel_dp_rate_index(intel_dp->common_rates, common_len, link_rate);
 }
 
 int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
 					    int link_rate, uint8_t lane_count)
 {
-	int common_rates[DP_MAX_SUPPORTED_RATES];
+	const int *common_rates = intel_dp->common_rates;
 	int link_rate_index;
 
-	link_rate_index = intel_dp_link_rate_index(intel_dp,
-						   common_rates,
-						   link_rate);
+	link_rate_index = intel_dp_link_rate_index(intel_dp, link_rate);
 	if (link_rate_index > 0) {
 		intel_dp->max_sink_link_rate = common_rates[link_rate_index - 1];
 		intel_dp->max_sink_lane_count = lane_count;

@@ -1506,8 +1516,6 @@ static void snprintf_int_array(char *str, size_t len,
 
 static void intel_dp_print_rates(struct intel_dp *intel_dp)
 {
-	int common_len;
-	int common_rates[DP_MAX_SUPPORTED_RATES];
 	char str[128]; /* FIXME: too big for stack? */
 
 	if ((drm_debug & DRM_UT_KMS) == 0)

@@ -1521,8 +1529,8 @@ static void intel_dp_print_rates(struct intel_dp *intel_dp)
 			   intel_dp->sink_rates, intel_dp->num_sink_rates);
 	DRM_DEBUG_KMS("sink rates: %s\n", str);
 
-	common_len = intel_dp_common_rates(intel_dp, common_rates);
-	snprintf_int_array(str, sizeof(str), common_rates, common_len);
+	snprintf_int_array(str, sizeof(str),
+			   intel_dp->common_rates, intel_dp->num_common_rates);
 	DRM_DEBUG_KMS("common rates: %s\n", str);
 }
 

@@ -1560,14 +1568,14 @@ bool intel_dp_read_desc(struct intel_dp *intel_dp)
 int
 intel_dp_max_link_rate(struct intel_dp *intel_dp)
 {
-	int rates[DP_MAX_SUPPORTED_RATES] = {};
 	int len;
 
-	len = intel_dp_common_rates(intel_dp, rates);
+	len = intel_dp_common_len_rate_limit(intel_dp,
+					     intel_dp->max_sink_link_rate);
 	if (WARN_ON(len <= 0))
 		return 162000;
 
-	return rates[len - 1];
+	return intel_dp->common_rates[len - 1];
 }
 
 int intel_dp_rate_select(struct intel_dp *intel_dp, int rate)

@@ -1636,11 +1644,11 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 	int link_rate_index;
 	int bpp, mode_rate;
 	int link_avail, link_clock;
-	int common_rates[DP_MAX_SUPPORTED_RATES] = {};
 	int common_len;
 	uint8_t link_bw, rate_select;
 
-	common_len = intel_dp_common_rates(intel_dp, common_rates);
+	common_len = intel_dp_common_len_rate_limit(intel_dp,
+						    intel_dp->max_sink_link_rate);
 
 	/* No common link rates between source and sink */
 	WARN_ON(common_len <= 0);

@@ -1678,7 +1686,6 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 	/* Use values requested by Compliance Test Request */
 	if (intel_dp->compliance.test_type == DP_TEST_LINK_TRAINING) {
 		link_rate_index = intel_dp_link_rate_index(intel_dp,
-							   common_rates,
 							   intel_dp->compliance.test_link_rate);
 		if (link_rate_index >= 0)
 			min_clock = max_clock = link_rate_index;

@@ -1686,7 +1693,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 	}
 	DRM_DEBUG_KMS("DP link computation with max lane count %i "
 		      "max bw %d pixel clock %iKHz\n",
-		      max_lane_count, common_rates[max_clock],
+		      max_lane_count, intel_dp->common_rates[max_clock],
 		      adjusted_mode->crtc_clock);
 
 	/* Walk through all bpp values. Luckily they're all nicely spaced with 2

@@ -1722,7 +1729,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 				lane_count <= max_lane_count;
 				lane_count <<= 1) {
 
-				link_clock = common_rates[clock];
+				link_clock = intel_dp->common_rates[clock];
 				link_avail = intel_dp_max_data_rate(link_clock,
 								    lane_count);
 

@@ -1754,7 +1761,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 	pipe_config->lane_count = lane_count;
 
 	pipe_config->pipe_bpp = bpp;
-	pipe_config->port_clock = common_rates[clock];
+	pipe_config->port_clock = intel_dp->common_rates[clock];
 
 	intel_dp_compute_rate(intel_dp, pipe_config->port_clock,
 			      &link_bw, &rate_select);

@@ -3715,6 +3722,8 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp)
 	else
 		intel_dp_set_sink_rates(intel_dp);
 
+	intel_dp_set_common_rates(intel_dp);
+
 	return true;
 }
 

@@ -3726,8 +3735,10 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
 		return false;
 
 	/* Don't clobber cached eDP rates. */
-	if (!is_edp(intel_dp))
+	if (!is_edp(intel_dp)) {
 		intel_dp_set_sink_rates(intel_dp);
+		intel_dp_set_common_rates(intel_dp);
+	}
 
 	if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT,
 			     &intel_dp->sink_count, 1) < 0)

@@ -3950,7 +3961,6 @@ static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
 {
 	int status = 0;
 	int min_lane_count = 1;
-	int common_rates[DP_MAX_SUPPORTED_RATES] = {};
 	int link_rate_index, test_link_rate;
 	uint8_t test_lane_count, test_link_bw;
 	/* (DP CTS 1.2)

@@ -3979,7 +3989,6 @@ static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
 	/* Validate the requested link rate */
 	test_link_rate = drm_dp_bw_code_to_link_rate(test_link_bw);
 	link_rate_index = intel_dp_link_rate_index(intel_dp,
-						   common_rates,
 						   test_link_rate);
 	if (link_rate_index < 0)
 		return DP_TEST_NAK;

drivers/gpu/drm/i915/intel_drv.h +3 -0

index f8140b06679d..ec8985b20616 100644
@@ -956,6 +956,9 @@ struct intel_dp {
 	int num_sink_rates;
 	int sink_rates[DP_MAX_SUPPORTED_RATES];
 	bool use_rate_select;
+	/* intersection of source and sink rates */
+	int num_common_rates;
+	int common_rates[DP_MAX_SUPPORTED_RATES];
 	/* Max lane count for the sink as per DPCD registers */
 	uint8_t max_sink_lane_count;
 	/* Max link BW for the sink as per DPCD registers */

Signature · 1 line

2.1.4

In link training fallback, we're trying to find a rate that we know is in a sorted array of common link rates. We don't need to limit the array using the max rate. For test request, the DP CTS doesn't say we should limit the rate based on earlier fallback.

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c | 31 ++++++++++++-------------------
 1 file changed, 12 insertions(+), 19 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +12 -19

index 1808af6d635d..8c061c54d481 100644
@@ -317,25 +317,16 @@ static int intel_dp_common_len_rate_limit(struct intel_dp *intel_dp,
 	return 0;
 }
 
-static int intel_dp_link_rate_index(struct intel_dp *intel_dp, int link_rate)
-{
-	int common_len;
-
-	common_len = intel_dp_common_len_rate_limit(intel_dp,
-						    intel_dp->max_sink_link_rate);
-
-	return intel_dp_rate_index(intel_dp->common_rates, common_len, link_rate);
-}
-
 int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
 					    int link_rate, uint8_t lane_count)
 {
-	const int *common_rates = intel_dp->common_rates;
-	int link_rate_index;
+	int index;
 
-	link_rate_index = intel_dp_link_rate_index(intel_dp, link_rate);
-	if (link_rate_index > 0) {
-		intel_dp->max_sink_link_rate = common_rates[link_rate_index - 1];
+	index = intel_dp_rate_index(intel_dp->common_rates,
+				    intel_dp->num_common_rates,
+				    link_rate);
+	if (index > 0) {
+		intel_dp->max_sink_link_rate = intel_dp->common_rates[index - 1];
 		intel_dp->max_sink_lane_count = lane_count;
 	} else if (lane_count > 1) {
 		intel_dp->max_sink_link_rate = intel_dp_max_sink_rate(intel_dp);

@@ -1685,8 +1676,9 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 
 	/* Use values requested by Compliance Test Request */
 	if (intel_dp->compliance.test_type == DP_TEST_LINK_TRAINING) {
-		link_rate_index = intel_dp_link_rate_index(intel_dp,
-							   intel_dp->compliance.test_link_rate);
+		link_rate_index = intel_dp_rate_index(intel_dp->common_rates,
+						      intel_dp->num_common_rates,
+						      intel_dp->compliance.test_link_rate);
 		if (link_rate_index >= 0)
 			min_clock = max_clock = link_rate_index;
 		min_lane_count = max_lane_count = intel_dp->compliance.test_lane_count;

@@ -3988,8 +3980,9 @@ static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
 	}
 	/* Validate the requested link rate */
 	test_link_rate = drm_dp_bw_code_to_link_rate(test_link_bw);
-	link_rate_index = intel_dp_link_rate_index(intel_dp,
-						   test_link_rate);
+	link_rate_index = intel_dp_rate_index(intel_dp->common_rates,
+					      intel_dp->num_common_rates,
+					      test_link_rate);
 	if (link_rate_index < 0)
 		return DP_TEST_NAK;
 

Signature · 1 line

2.1.4

In link training fallback, we're trying to find a rate that we know is in a sorted array of common link rates. We don't need to limit the array using the max rate. For test request, the DP CTS doesn't say we should limit the rate based on earlier fallback. This lets us get rid of intel_dp_link_rate_index() and use intel_dp_rate_index() instead.

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---

updated commit message, no changes

---
 drivers/gpu/drm/i915/intel_dp.c | 31 ++++++++++++-------------------
 1 file changed, 12 insertions(+), 19 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +12 -19

index 1808af6d635d..8c061c54d481 100644
@@ -317,25 +317,16 @@ static int intel_dp_common_len_rate_limit(struct intel_dp *intel_dp,
 	return 0;
 }
 
-static int intel_dp_link_rate_index(struct intel_dp *intel_dp, int link_rate)
-{
-	int common_len;
-
-	common_len = intel_dp_common_len_rate_limit(intel_dp,
-						    intel_dp->max_sink_link_rate);
-
-	return intel_dp_rate_index(intel_dp->common_rates, common_len, link_rate);
-}
-
 int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
 					    int link_rate, uint8_t lane_count)
 {
-	const int *common_rates = intel_dp->common_rates;
-	int link_rate_index;
+	int index;
 
-	link_rate_index = intel_dp_link_rate_index(intel_dp, link_rate);
-	if (link_rate_index > 0) {
-		intel_dp->max_sink_link_rate = common_rates[link_rate_index - 1];
+	index = intel_dp_rate_index(intel_dp->common_rates,
+				    intel_dp->num_common_rates,
+				    link_rate);
+	if (index > 0) {
+		intel_dp->max_sink_link_rate = intel_dp->common_rates[index - 1];
 		intel_dp->max_sink_lane_count = lane_count;
 	} else if (lane_count > 1) {
 		intel_dp->max_sink_link_rate = intel_dp_max_sink_rate(intel_dp);

@@ -1685,8 +1676,9 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 
 	/* Use values requested by Compliance Test Request */
 	if (intel_dp->compliance.test_type == DP_TEST_LINK_TRAINING) {
-		link_rate_index = intel_dp_link_rate_index(intel_dp,
-							   intel_dp->compliance.test_link_rate);
+		link_rate_index = intel_dp_rate_index(intel_dp->common_rates,
+						      intel_dp->num_common_rates,
+						      intel_dp->compliance.test_link_rate);
 		if (link_rate_index >= 0)
 			min_clock = max_clock = link_rate_index;
 		min_lane_count = max_lane_count = intel_dp->compliance.test_lane_count;

@@ -3988,8 +3980,9 @@ static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
 	}
 	/* Validate the requested link rate */
 	test_link_rate = drm_dp_bw_code_to_link_rate(test_link_bw);
-	link_rate_index = intel_dp_link_rate_index(intel_dp,
-						   test_link_rate);
+	link_rate_index = intel_dp_rate_index(intel_dp->common_rates,
+					      intel_dp->num_common_rates,
+					      test_link_rate);
 	if (link_rate_index < 0)
 		return DP_TEST_NAK;
 

Signature · 1 line

2.1.4

If we modify these on the fly depending on the link conditions, don't pretend they are sink properties.

Some link vs. sink confusion still remains, but we'll take care of them in follow-up patches.

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c  | 25 ++++++++++++-------------
 drivers/gpu/drm/i915/intel_drv.h |  8 ++++----
 2 files changed, 16 insertions(+), 17 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +12 -13

index 8c061c54d481..a0082a3784e8 100644
@@ -172,7 +172,7 @@ static u8 intel_dp_max_lane_count(struct intel_dp *intel_dp)
 	u8 source_max, sink_max;
 
 	source_max = intel_dig_port->max_lanes;
-	sink_max = intel_dp->max_sink_lane_count;
+	sink_max = intel_dp->max_link_lane_count;
 
 	return min(source_max, sink_max);
 }

@@ -326,11 +326,11 @@ int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
 				    intel_dp->num_common_rates,
 				    link_rate);
 	if (index > 0) {
-		intel_dp->max_sink_link_rate = intel_dp->common_rates[index - 1];
-		intel_dp->max_sink_lane_count = lane_count;
+		intel_dp->max_link_rate = intel_dp->common_rates[index - 1];
+		intel_dp->max_link_lane_count = lane_count;
 	} else if (lane_count > 1) {
-		intel_dp->max_sink_link_rate = intel_dp_max_sink_rate(intel_dp);
-		intel_dp->max_sink_lane_count = lane_count >> 1;
+		intel_dp->max_link_rate = intel_dp_max_sink_rate(intel_dp);
+		intel_dp->max_link_lane_count = lane_count >> 1;
 	} else {
 		DRM_ERROR("Link Training Unsuccessful\n");
 		return -1;

@@ -1561,8 +1561,7 @@ intel_dp_max_link_rate(struct intel_dp *intel_dp)
 {
 	int len;
 
-	len = intel_dp_common_len_rate_limit(intel_dp,
-					     intel_dp->max_sink_link_rate);
+	len = intel_dp_common_len_rate_limit(intel_dp, intel_dp->max_link_rate);
 	if (WARN_ON(len <= 0))
 		return 162000;
 

@@ -1639,7 +1638,7 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 	uint8_t link_bw, rate_select;
 
 	common_len = intel_dp_common_len_rate_limit(intel_dp,
-						    intel_dp->max_sink_link_rate);
+						    intel_dp->max_link_rate);
 
 	/* No common link rates between source and sink */
 	WARN_ON(common_len <= 0);

@@ -3969,7 +3968,7 @@ static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
 	test_lane_count &= DP_MAX_LANE_COUNT_MASK;
 	/* Validate the requested lane count */
 	if (test_lane_count < min_lane_count ||
-	    test_lane_count > intel_dp->max_sink_lane_count)
+	    test_lane_count > intel_dp->max_link_lane_count)
 		return DP_TEST_NAK;
 
 	status = drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_LINK_RATE,

@@ -4637,11 +4636,11 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
 		      yesno(drm_dp_tps3_supported(intel_dp->dpcd)));
 
 	if (intel_dp->reset_link_params) {
-		/* Set the max lane count for sink */
-		intel_dp->max_sink_lane_count = drm_dp_max_lane_count(intel_dp->dpcd);
+		/* Set the max lane count for link */
+		intel_dp->max_link_lane_count = drm_dp_max_lane_count(intel_dp->dpcd);
 
-		/* Set the max link rate for sink */
-		intel_dp->max_sink_link_rate = intel_dp_max_sink_rate(intel_dp);
+		/* Set the max link rate for link */
+		intel_dp->max_link_rate = intel_dp_max_sink_rate(intel_dp);
 
 		intel_dp->reset_link_params = false;
 	}

drivers/gpu/drm/i915/intel_drv.h +4 -4

index ec8985b20616..9141515e4204 100644
@@ -959,10 +959,10 @@ struct intel_dp {
 	/* intersection of source and sink rates */
 	int num_common_rates;
 	int common_rates[DP_MAX_SUPPORTED_RATES];
-	/* Max lane count for the sink as per DPCD registers */
-	uint8_t max_sink_lane_count;
-	/* Max link BW for the sink as per DPCD registers */
-	int max_sink_link_rate;
+	/* Max lane count for the current link */
+	int max_link_lane_count;
+	/* Max rate for the current link */
+	int max_link_rate;
 	/* sink or branch descriptor */
 	struct intel_dp_desc desc;
 	struct drm_dp_aux aux;

Signature · 1 line

2.1.4

These are the theoretical maximums common for source and sink. These are the maximums we should start with. They may be degraded in case of link training failures, and the dynamic link values are stored separately.

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +17 -12

index a0082a3784e8..b3df2082eac9 100644
@@ -161,22 +161,27 @@ static void intel_dp_set_sink_rates(struct intel_dp *intel_dp)
 	intel_dp->num_sink_rates = num_rates;
 }
 
-static int intel_dp_max_sink_rate(struct intel_dp *intel_dp)
+/* Theoretical max between source and sink */
+static int intel_dp_max_common_rate(struct intel_dp *intel_dp)
 {
-	return intel_dp->sink_rates[intel_dp->num_sink_rates - 1];
+	return intel_dp->common_rates[intel_dp->num_common_rates - 1];
 }
 
-static u8 intel_dp_max_lane_count(struct intel_dp *intel_dp)
+/* Theoretical max between source and sink */
+static int intel_dp_max_common_lane_count(struct intel_dp *intel_dp)
 {
 	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
-	u8 source_max, sink_max;
-
-	source_max = intel_dig_port->max_lanes;
-	sink_max = intel_dp->max_link_lane_count;
+	int source_max = intel_dig_port->max_lanes;
+	int sink_max = drm_dp_max_lane_count(intel_dp->dpcd);
 
 	return min(source_max, sink_max);
 }
 
+static int intel_dp_max_lane_count(struct intel_dp *intel_dp)
+{
+	return intel_dp->max_link_lane_count;
+}
+
 int
 intel_dp_link_required(int pixel_clock, int bpp)
 {

@@ -329,7 +334,7 @@ int intel_dp_get_link_train_fallback_values(struct intel_dp *intel_dp,
 		intel_dp->max_link_rate = intel_dp->common_rates[index - 1];
 		intel_dp->max_link_lane_count = lane_count;
 	} else if (lane_count > 1) {
-		intel_dp->max_link_rate = intel_dp_max_sink_rate(intel_dp);
+		intel_dp->max_link_rate = intel_dp_max_common_rate(intel_dp);
 		intel_dp->max_link_lane_count = lane_count >> 1;
 	} else {
 		DRM_ERROR("Link Training Unsuccessful\n");

@@ -4636,11 +4641,11 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
 		      yesno(drm_dp_tps3_supported(intel_dp->dpcd)));
 
 	if (intel_dp->reset_link_params) {
-		/* Set the max lane count for link */
-		intel_dp->max_link_lane_count = drm_dp_max_lane_count(intel_dp->dpcd);
+		/* Initial max link lane count */
+		intel_dp->max_link_lane_count = intel_dp_max_common_lane_count(intel_dp);
 
-		/* Set the max link rate for link */
-		intel_dp->max_link_rate = intel_dp_max_sink_rate(intel_dp);
+		/* Initial max link rate */
+		intel_dp->max_link_rate = intel_dp_max_common_rate(intel_dp);
 
 		intel_dp->reset_link_params = false;
 	}

Signature · 1 line

2.1.4

The source might not support as many lanes as the sink, or the link training might have failed at higher lane counts. Take these into account.

Cc Dhinakaran Pandiyan <[email protected]>

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c     | 2 +-
 drivers/gpu/drm/i915/intel_dp_mst.c | 4 ++--
 drivers/gpu/drm/i915/intel_drv.h    | 1 +
 3 files changed, 4 insertions(+), 3 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +1 -1

index b3df2082eac9..95f2278700e3 100644
@@ -177,7 +177,7 @@ static int intel_dp_max_common_lane_count(struct intel_dp *intel_dp)
 	return min(source_max, sink_max);
 }
 
-static int intel_dp_max_lane_count(struct intel_dp *intel_dp)
+int intel_dp_max_lane_count(struct intel_dp *intel_dp)
 {
 	return intel_dp->max_link_lane_count;
 }

drivers/gpu/drm/i915/intel_dp_mst.c +2 -2

index c1f62eb07c07..3451e2abb23b 100644
@@ -56,7 +56,7 @@ static bool intel_dp_mst_compute_config(struct intel_encoder *encoder,
 	 * for MST we always configure max link bw - the spec doesn't
 	 * seem to suggest we should do otherwise.
 	 */
-	lane_count = drm_dp_max_lane_count(intel_dp->dpcd);
+	lane_count = intel_dp_max_lane_count(intel_dp);
 
 	pipe_config->lane_count = lane_count;
 

@@ -343,7 +343,7 @@ intel_dp_mst_mode_valid(struct drm_connector *connector,
 	int max_rate, mode_rate, max_lanes, max_link_clock;
 
 	max_link_clock = intel_dp_max_link_rate(intel_dp);
-	max_lanes = drm_dp_max_lane_count(intel_dp->dpcd);
+	max_lanes = intel_dp_max_lane_count(intel_dp);
 
 	max_rate = intel_dp_max_data_rate(max_link_clock, max_lanes);
 	mode_rate = intel_dp_link_required(mode->clock, bpp);

drivers/gpu/drm/i915/intel_drv.h +1 -0

index 9141515e4204..0c037295459b 100644
@@ -1507,6 +1507,7 @@ void intel_dp_add_properties(struct intel_dp *intel_dp, struct drm_connector *co
 void intel_dp_mst_suspend(struct drm_device *dev);
 void intel_dp_mst_resume(struct drm_device *dev);
 int intel_dp_max_link_rate(struct intel_dp *intel_dp);
+int intel_dp_max_lane_count(struct intel_dp *intel_dp);
 int intel_dp_rate_select(struct intel_dp *intel_dp, int rate);
 void intel_dp_hot_plug(struct intel_encoder *intel_encoder);
 void intel_power_sequencer_reset(struct drm_i915_private *dev_priv);

Signature · 1 line

2.1.4

Localize link_rate_index to the if block, and rename to just index to reduce indent.

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +7 -6

index 95f2278700e3..6f743490855b 100644
@@ -1636,7 +1636,6 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 	/* Conveniently, the link BW constants become indices with a shift...*/
 	int min_clock = 0;
 	int max_clock;
-	int link_rate_index;
 	int bpp, mode_rate;
 	int link_avail, link_clock;
 	int common_len;

@@ -1680,11 +1679,13 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 
 	/* Use values requested by Compliance Test Request */
 	if (intel_dp->compliance.test_type == DP_TEST_LINK_TRAINING) {
-		link_rate_index = intel_dp_rate_index(intel_dp->common_rates,
-						      intel_dp->num_common_rates,
-						      intel_dp->compliance.test_link_rate);
-		if (link_rate_index >= 0)
-			min_clock = max_clock = link_rate_index;
+		int index;
+
+		index = intel_dp_rate_index(intel_dp->common_rates,
+					    intel_dp->num_common_rates,
+					    intel_dp->compliance.test_link_rate);
+		if (index >= 0)
+			min_clock = max_clock = index;
 		min_lane_count = max_lane_count = intel_dp->compliance.test_lane_count;
 	}
 	DRM_DEBUG_KMS("DP link computation with max lane count %i "

Signature · 1 line

2.1.4

Why not squash this with patch 08/14? and call it cleanup for obtaining the rate index using intel_dp_rate_index()
Just a thought..

Regards
Manasi

Quoted 44 lines · Jani Nikula

Localize link_rate_index to the if block, and rename to just index to reduce indent.

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +7 -6

index 95f2278700e3..6f743490855b 100644
@@ -1636,7 +1636,6 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 	/* Conveniently, the link BW constants become indices with a shift...*/
 	int min_clock = 0;
 	int max_clock;
-	int link_rate_index;
 	int bpp, mode_rate;
 	int link_avail, link_clock;
 	int common_len;

@@ -1680,11 +1679,13 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 
 	/* Use values requested by Compliance Test Request */
 	if (intel_dp->compliance.test_type == DP_TEST_LINK_TRAINING) {
-		link_rate_index = intel_dp_rate_index(intel_dp->common_rates,
-						      intel_dp->num_common_rates,
-						      intel_dp->compliance.test_link_rate);
-		if (link_rate_index >= 0)
-			min_clock = max_clock = link_rate_index;
+		int index;
+
+		index = intel_dp_rate_index(intel_dp->common_rates,
+					    intel_dp->num_common_rates,
+					    intel_dp->compliance.test_link_rate);
+		if (index >= 0)
+			min_clock = max_clock = index;
 		min_lane_count = max_lane_count = intel_dp->compliance.test_lane_count;
 	}
 	DRM_DEBUG_KMS("DP link computation with max lane count %i "

Signature · 1 line

2.1.4

Quoted 3 lines · Manasi Navare

Why not squash this with patch 08/14? and call it cleanup for obtaining the rate index using intel_dp_rate_index()
Just a thought..

Again, usually too big patches are the problem, not the other way around.

BR,
Jani.

Quoted 11 lines

Regards
Manasi

Quoted 6 lines · Jani Nikula

Localize link_rate_index to the if block, and rename to just index to reduce indent.

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

Quoted 30 lines

Quoted 30 lines

---
 drivers/gpu/drm/i915/intel_dp.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +5 -6

index 95f2278700e3..6f743490855b 100644
@@ -1636,7 +1636,6 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 	/* Conveniently, the link BW constants become indices with a shift...*/
 	int min_clock = 0;
 	int max_clock;
-	int link_rate_index;
 	int bpp, mode_rate;
 	int link_avail, link_clock;
 	int common_len;

@@ -1680,11 +1679,13 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 
 	/* Use values requested by Compliance Test Request */
 	if (intel_dp->compliance.test_type == DP_TEST_LINK_TRAINING) {
-		link_rate_index = intel_dp_rate_index(intel_dp->common_rates,
-						      intel_dp->num_common_rates,
-						      intel_dp->compliance.test_link_rate);
-		if (link_rate_index >= 0)
-			min_clock = max_clock = link_rate_index;
+		int index;
+
+		index = intel_dp_rate_index(intel_dp->common_rates,
+					    intel_dp->num_common_rates,
+					    intel_dp->compliance.test_link_rate);

Quoted 8 lines

Quoted 8 lines

drivers/gpu/drm/i915/intel_dp.c +2 -0

+		if (index >= 0)
+			min_clock = max_clock = index;
 		min_lane_count = max_lane_count = intel_dp->compliance.test_lane_count;
 	}
 	DRM_DEBUG_KMS("DP link computation with max lane count %i "

Signature · 1 line

2.1.4

Signature · 1 line

Jani Nikula, Intel Open Source Technology Center

This is what we have the readb and writeb variants for. Do some minor return value and variable cleanup while at it.

Cc Manasi Navare <[email protected]>

Cc Ville Syrjälä <[email protected]>

Signed-off-by Jani Nikula <[email protected]>

---
 drivers/gpu/drm/i915/intel_dp.c | 37 +++++++++++++++++--------------------
 1 file changed, 17 insertions(+), 20 deletions(-)

drivers/gpu/drm/i915/intel_dp.c +17 -20

index 6f743490855b..81682fd2804b 100644
@@ -3661,9 +3661,9 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp)
 		uint8_t frame_sync_cap;
 
 		dev_priv->psr.sink_support = true;
-		drm_dp_dpcd_read(&intel_dp->aux,
-				 DP_SINK_DEVICE_AUX_FRAME_SYNC_CAP,
-				 &frame_sync_cap, 1);
+		drm_dp_dpcd_readb(&intel_dp->aux,
+				  DP_SINK_DEVICE_AUX_FRAME_SYNC_CAP,
+				  &frame_sync_cap);
 		dev_priv->psr.aux_frame_sync = frame_sync_cap ? true : false;
 		/* PSR2 needs frame sync as well */
 		dev_priv->psr.psr2_support = dev_priv->psr.aux_frame_sync;

@@ -3737,8 +3737,8 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
 		intel_dp_set_common_rates(intel_dp);
 	}
 
-	if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT,
-			     &intel_dp->sink_count, 1) < 0)
+	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_SINK_COUNT,
+			      &intel_dp->sink_count) <= 0)
 		return false;
 
 	/*

@@ -3775,7 +3775,7 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
 static bool
 intel_dp_can_mst(struct intel_dp *intel_dp)
 {
-	u8 buf[1];
+	u8 mstm_cap;
 
 	if (!i915.enable_dp_mst)
 		return false;

@@ -3786,10 +3786,10 @@ intel_dp_can_mst(struct intel_dp *intel_dp)
 	if (intel_dp->dpcd[DP_DPCD_REV] < 0x12)
 		return false;
 
-	if (drm_dp_dpcd_read(&intel_dp->aux, DP_MSTM_CAP, buf, 1) != 1)
+	if (drm_dp_dpcd_readb(&intel_dp->aux, DP_MSTM_CAP, &mstm_cap) != 1)
 		return false;
 
-	return buf[0] & DP_MST_CAP;
+	return mstm_cap & DP_MST_CAP;
 }
 
 static void

@@ -3935,9 +3935,8 @@ int intel_dp_sink_crc(struct intel_dp *intel_dp, u8 *crc)
 static bool
 intel_dp_get_sink_irq(struct intel_dp *intel_dp, u8 *sink_irq_vector)
 {
-	return drm_dp_dpcd_read(&intel_dp->aux,
-				       DP_DEVICE_SERVICE_IRQ_VECTOR,
-				       sink_irq_vector, 1) == 1;
+	return drm_dp_dpcd_readb(&intel_dp->aux, DP_DEVICE_SERVICE_IRQ_VECTOR,
+				 sink_irq_vector) == 1;
 }
 
 static bool

@@ -4000,13 +3999,13 @@ static uint8_t intel_dp_autotest_link_training(struct intel_dp *intel_dp)
 static uint8_t intel_dp_autotest_video_pattern(struct intel_dp *intel_dp)
 {
 	uint8_t test_pattern;
-	uint16_t test_misc;
+	uint8_t test_misc;
 	__be16 h_width, v_height;
 	int status = 0;
 
 	/* Read the TEST_PATTERN (DP CTS 3.1.5) */
-	status = drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_PATTERN,
-				  &test_pattern, 1);
+	status = drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_PATTERN,
+				   &test_pattern);
 	if (status <= 0) {
 		DRM_DEBUG_KMS("Test pattern read failed\n");
 		return DP_TEST_NAK;

@@ -4028,8 +4027,8 @@ static uint8_t intel_dp_autotest_video_pattern(struct intel_dp *intel_dp)
 		return DP_TEST_NAK;
 	}
 
-	status = drm_dp_dpcd_read(&intel_dp->aux, DP_TEST_MISC0,
-				  &test_misc, 1);
+	status = drm_dp_dpcd_readb(&intel_dp->aux, DP_TEST_MISC0,
+				   &test_misc);
 	if (status <= 0) {
 		DRM_DEBUG_KMS("TEST MISC read failed\n");
 		return DP_TEST_NAK;

@@ -4088,10 +4087,8 @@ static uint8_t intel_dp_autotest_edid(struct intel_dp *intel_dp)
 		 */
 		block += intel_connector->detect_edid->extensions;
 
-		if (!drm_dp_dpcd_write(&intel_dp->aux,
-					DP_TEST_EDID_CHECKSUM,
-					&block->checksum,
-					1))
+		if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_TEST_EDID_CHECKSUM,
+				       block->checksum) <= 0)
 			DRM_DEBUG_KMS("Failed to write EDID checksum\n");
 
 		test_result = DP_TEST_ACK | DP_TEST_EDID_CHECKSUM_WRITE;

Signature · 1 line

2.1.4