FAILED: patch "[PATCH] drm/i915/hdmi: Turn DP++ TMDS output buffers back on in" failed to apply to 5.15-stable tree

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From cecbc0c7eba7983965cac94f88d2db00b913253b Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <[email protected]>
Date: Fri, 29 Oct 2021 22:18:02 +0300
Subject: [PATCH] drm/i915/hdmi: Turn DP++ TMDS output buffers back on in
encoder->shutdown()
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Looks like our VBIOS/GOP generally fail to turn the DP dual mode adater TMDS output buffers back on after a reboot. This leads to a black screen after reboot if we turned the TMDS output buffers off prior to reboot. And if i915 decides to do a fastboot the black screen will persist even after i915 takes over.

Apparently this has been a problem ever since commit b2ccb822d376 ("drm/i915:
Enable/disable TMDS output buffers in DP++ adaptor as needed") if one rebooted while the display was turned off. And things became worse with commit fe0f1e3bfdfe ("drm/i915: Shut down displays gracefully on reboot") since now we always turn the display off before a reboot.

This was reported on a RKL, but I confirmed the same behaviour on my SNB as well. So looks pretty universal.

Let's fix this by explicitly turning the TMDS output buffers back on in the encoder->shutdown() hook. Note that this gets called after irqs have been disabled, so the i2c communication with the DP dual mode adapter has to be performed via polling (which the gmbus code is perfectly happy to do for us).

We also need a bit of care in handling DDI encoders which may or may not be set up for HDMI output. Specifically ddc_pin will not be populated for a DP only DDI encoder, in which case we don't want to call intel_gmbus_get_adapter(). We can handle that by simply doing the dual mode adapter type check before calling intel_gmbus_get_adapter().

Cc <[email protected]> # v5.11+

Fixes fe0f1e3bfdfe ("drm/i915: Shut down displays gracefully on reboot")

Closes https://gitlab.freedesktop.org/drm/intel/-/issues/4371

Signed-off-by Ville Syrjälä <[email protected]>

Link https://patchwork.freedesktop.org/patch/msgid/[email protected]

Reviewed-by Stanislav Lisovskiy <[email protected]>

(cherry picked from commit 49c55f7b035b87371a6d3c53d9af9f92ddc962db)

Signed-off-by Rodrigo Vivi <[email protected]>

drivers/gpu/drm/i915/display/g4x_hdmi.c +1 -0

index 88c427f3c346..f5b4dd5b4275 100644
@@ -584,6 +584,7 @@ void g4x_hdmi_init(struct drm_i915_private *dev_priv,
 		else
 			intel_encoder->enable = g4x_enable_hdmi;
 	}
+	intel_encoder->shutdown = intel_hdmi_encoder_shutdown;
 
 	intel_encoder->type = INTEL_OUTPUT_HDMI;
 	intel_encoder->power_domain = intel_port_to_power_domain(port);

drivers/gpu/drm/i915/display/intel_ddi.c +1 -0

index 1dcfe31e6c6f..cfb567df71b3 100644
@@ -4361,6 +4361,7 @@ static void intel_ddi_encoder_shutdown(struct intel_encoder *encoder)
 	enum phy phy = intel_port_to_phy(i915, encoder->port);
 
 	intel_dp_encoder_shutdown(encoder);
+	intel_hdmi_encoder_shutdown(encoder);
 
 	if (!intel_phy_is_tc(i915, phy))
 		return;

drivers/gpu/drm/i915/display/intel_hdmi.c +14 -2

index d2e61f6c6e08..371736bdc01f 100644
@@ -1246,12 +1246,13 @@ static void hsw_set_infoframes(struct intel_encoder *encoder,
 void intel_dp_dual_mode_set_tmds_output(struct intel_hdmi *hdmi, bool enable)
 {
 	struct drm_i915_private *dev_priv = intel_hdmi_to_i915(hdmi);
-	struct i2c_adapter *adapter =
-		intel_gmbus_get_adapter(dev_priv, hdmi->ddc_bus);
+	struct i2c_adapter *adapter;
 
 	if (hdmi->dp_dual_mode.type < DRM_DP_DUAL_MODE_TYPE2_DVI)
 		return;
 
+	adapter = intel_gmbus_get_adapter(dev_priv, hdmi->ddc_bus);
+
 	drm_dbg_kms(&dev_priv->drm, "%s DP dual mode adaptor TMDS output\n",
 		    enable ? "Enabling" : "Disabling");
 

@@ -2258,6 +2259,17 @@ int intel_hdmi_compute_config(struct intel_encoder *encoder,
 	return 0;
 }
 
+void intel_hdmi_encoder_shutdown(struct intel_encoder *encoder)
+{
+	struct intel_hdmi *intel_hdmi = enc_to_intel_hdmi(encoder);
+
+	/*
+	 * Give a hand to buggy BIOSen which forget to turn
+	 * the TMDS output buffers back on after a reboot.
+	 */
+	intel_dp_dual_mode_set_tmds_output(intel_hdmi, true);
+}
+
 static void
 intel_hdmi_unset_edid(struct drm_connector *connector)
 {

drivers/gpu/drm/i915/display/intel_hdmi.h +1 -0

index b43a180d007e..2bf440eb400a 100644
@@ -28,6 +28,7 @@ void intel_hdmi_init_connector(struct intel_digital_port *dig_port,
 int intel_hdmi_compute_config(struct intel_encoder *encoder,
 			      struct intel_crtc_state *pipe_config,
 			      struct drm_connector_state *conn_state);
+void intel_hdmi_encoder_shutdown(struct intel_encoder *encoder);
 bool intel_hdmi_handle_sink_scrambling(struct intel_encoder *encoder,
 				       struct drm_connector *connector,
 				       bool high_tmds_clock_ratio,

Quoted 5 lines · On Tue, Nov 23, 2021 at 12:52:02PM +0100, [email protected] wrote:

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Looks like cherry-picking
commit 7ceb751b6159 ("drm/i915/hdmi: convert intel_hdmi_to_dev to intel_hdmi_to_i915") should solve the conflict with this one.