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From: Lyude Paul <lyude@redhat.com>
To: intel-gfx@lists.freedesktop.org
Cc: "Jani Nikula" <jani.nikula@intel.com>,
	"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
	"Jani Nikula" <jani.nikula@linux.intel.com>,
	"Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>,
	"Rodrigo Vivi" <rodrigo.vivi@intel.com>,
	"David Airlie" <airlied@linux.ie>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	"Sean Paul" <seanpaul@chromium.org>,
	"Aaron Ma" <aaron.ma@canonical.com>,
	"Dave Airlie" <airlied@redhat.com>,
	dri-devel@lists.freedesktop.org (open list:DRM DRIVERS),
	linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] drm/i915/dp: Don't use DPCD backlights that need PWM enable/disable
Date: Thu, 21 Jan 2021 13:36:43 -0500	[thread overview]
Message-ID: <20210121183644.2627282-1-lyude@redhat.com> (raw)

We haven't yet implemented support for backlights that need to be
enabled/disabled via PWM instead of AUX, which means we'll break things if
we enable DPCD backlight control on these machines. Luckily though since
most of these machines work fine just using the plain PWM backlight
controls anyway, there shouldn't be any issue with just leaving DPCD
backlight controls disabled in such situations.

This should fix the issues with PWM being left on that were being observed
on fi-bdw-samus.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Fixes: 4a8d79901d5b ("drm/i915/dp: Enable Intel's HDR backlight interface (only SDR for now)")
Testcase: igt/gem_exec_suspend/basic-s0 # fi-bdw-samus
Cc: Lyude Paul <lyude@redhat.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
index 31a478f63d52..651884390137 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -586,9 +586,14 @@ intel_dp_aux_supports_vesa_backlight(struct intel_connector *connector)
 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
 
 	/* Check the eDP Display control capabilities registers to determine if
-	 * the panel can support backlight control over the aux channel
+	 * the panel can support backlight control over the aux channel.
+	 *
+	 * TODO: We currently only support AUX only backlight configurations, not backlights which
+	 * require a mix of PWM and AUX controls to work. In the mean time, these machines typically
+	 * work just fine using normal PWM controls anyway.
 	 */
 	if (intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
+	    (intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
 	    (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP)) {
 		drm_dbg_kms(&i915->drm, "AUX Backlight Control Supported!\n");
 		return true;
-- 
2.29.2


WARNING: multiple messages have this Message-ID (diff)
From: Lyude Paul <lyude@redhat.com>
To: intel-gfx@lists.freedesktop.org
Cc: Jani Nikula <jani.nikula@intel.com>,
	open list <linux-kernel@vger.kernel.org>,
	David Airlie <airlied@linux.ie>,
	Sean Paul <seanpaul@chromium.org>,
	"open list:DRM DRIVERS" <dri-devel@lists.freedesktop.org>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	Aaron Ma <aaron.ma@canonical.com>,
	Dave Airlie <airlied@redhat.com>
Subject: [PATCH] drm/i915/dp: Don't use DPCD backlights that need PWM enable/disable
Date: Thu, 21 Jan 2021 13:36:43 -0500	[thread overview]
Message-ID: <20210121183644.2627282-1-lyude@redhat.com> (raw)

We haven't yet implemented support for backlights that need to be
enabled/disabled via PWM instead of AUX, which means we'll break things if
we enable DPCD backlight control on these machines. Luckily though since
most of these machines work fine just using the plain PWM backlight
controls anyway, there shouldn't be any issue with just leaving DPCD
backlight controls disabled in such situations.

This should fix the issues with PWM being left on that were being observed
on fi-bdw-samus.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Fixes: 4a8d79901d5b ("drm/i915/dp: Enable Intel's HDR backlight interface (only SDR for now)")
Testcase: igt/gem_exec_suspend/basic-s0 # fi-bdw-samus
Cc: Lyude Paul <lyude@redhat.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
index 31a478f63d52..651884390137 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -586,9 +586,14 @@ intel_dp_aux_supports_vesa_backlight(struct intel_connector *connector)
 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
 
 	/* Check the eDP Display control capabilities registers to determine if
-	 * the panel can support backlight control over the aux channel
+	 * the panel can support backlight control over the aux channel.
+	 *
+	 * TODO: We currently only support AUX only backlight configurations, not backlights which
+	 * require a mix of PWM and AUX controls to work. In the mean time, these machines typically
+	 * work just fine using normal PWM controls anyway.
 	 */
 	if (intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
+	    (intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
 	    (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP)) {
 		drm_dbg_kms(&i915->drm, "AUX Backlight Control Supported!\n");
 		return true;
-- 
2.29.2

_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

WARNING: multiple messages have this Message-ID (diff)
From: Lyude Paul <lyude@redhat.com>
To: intel-gfx@lists.freedesktop.org
Cc: Jani Nikula <jani.nikula@intel.com>,
	open list <linux-kernel@vger.kernel.org>,
	David Airlie <airlied@linux.ie>,
	Sean Paul <seanpaul@chromium.org>,
	"open list:DRM DRIVERS" <dri-devel@lists.freedesktop.org>,
	Aaron Ma <aaron.ma@canonical.com>,
	Dave Airlie <airlied@redhat.com>
Subject: [Intel-gfx] [PATCH] drm/i915/dp: Don't use DPCD backlights that need PWM enable/disable
Date: Thu, 21 Jan 2021 13:36:43 -0500	[thread overview]
Message-ID: <20210121183644.2627282-1-lyude@redhat.com> (raw)

We haven't yet implemented support for backlights that need to be
enabled/disabled via PWM instead of AUX, which means we'll break things if
we enable DPCD backlight control on these machines. Luckily though since
most of these machines work fine just using the plain PWM backlight
controls anyway, there shouldn't be any issue with just leaving DPCD
backlight controls disabled in such situations.

This should fix the issues with PWM being left on that were being observed
on fi-bdw-samus.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Fixes: 4a8d79901d5b ("drm/i915/dp: Enable Intel's HDR backlight interface (only SDR for now)")
Testcase: igt/gem_exec_suspend/basic-s0 # fi-bdw-samus
Cc: Lyude Paul <lyude@redhat.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
index 31a478f63d52..651884390137 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -586,9 +586,14 @@ intel_dp_aux_supports_vesa_backlight(struct intel_connector *connector)
 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
 
 	/* Check the eDP Display control capabilities registers to determine if
-	 * the panel can support backlight control over the aux channel
+	 * the panel can support backlight control over the aux channel.
+	 *
+	 * TODO: We currently only support AUX only backlight configurations, not backlights which
+	 * require a mix of PWM and AUX controls to work. In the mean time, these machines typically
+	 * work just fine using normal PWM controls anyway.
 	 */
 	if (intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
+	    (intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP) &&
 	    (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP)) {
 		drm_dbg_kms(&i915->drm, "AUX Backlight Control Supported!\n");
 		return true;
-- 
2.29.2

_______________________________________________
Intel-gfx mailing list
Intel-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

             reply	other threads:[~2021-01-21 18:40 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-21 18:36 Lyude Paul [this message]
2021-01-21 18:36 ` [Intel-gfx] [PATCH] drm/i915/dp: Don't use DPCD backlights that need PWM enable/disable Lyude Paul
2021-01-21 18:36 ` Lyude Paul
2021-01-22  2:40 ` [Intel-gfx] ✗ Fi.CI.BAT: failure for " Patchwork

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