FAILED: patch "[PATCH] drm/i915: Add support for panels with VESA backlights with" failed to apply to 04f0d6cc62cc1eaf9242c081520c024a17ba86a3-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 04f0d6cc62cc1eaf9242c081520c024a17ba86a3-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 <stable@vger.kernel.org>.

thanks,

greg k-h

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

From 04f0d6cc62cc1eaf9242c081520c024a17ba86a3 Mon Sep 17 00:00:00 2001
From: Lyude Paul <lyude@redhat.com>
Date: Fri, 5 Nov 2021 14:33:38 -0400
Subject: [PATCH] drm/i915: Add support for panels with VESA backlights with
 PWM enable/disable
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

This simply adds proper support for panel backlights that can be controlled
via VESA's backlight control protocol, but which also require that we
enable and disable the backlight via PWM instead of via the DPCD interface.
We also enable this by default, in order to fix some people's backlights
that were broken by not having this enabled.

For reference, backlights that require this and use VESA's backlight
interface tend to be laptops with hybrid GPUs, but this very well may
change in the future.

v4:
* Make sure that we call intel_backlight_level_to_pwm() in
  intel_dp_aux_vesa_enable_backlight() - vsyrjala

Signed-off-by: Lyude Paul <lyude@redhat.com>
Link: https://gitlab.freedesktop.org/drm/intel/-/issues/3680
Fixes: fe7d52bccab6 ("drm/i915/dp: Don't use DPCD backlights that need PWM enable/disable")
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.12+
Link: https://patchwork.freedesktop.org/patch/msgid/20211105183342.130810-2-lyude@redhat.com

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 569d17b4d00f..f05b71c01b8e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -293,6 +293,13 @@ intel_dp_aux_vesa_enable_backlight(const struct intel_crtc_state *crtc_state,
 	struct intel_panel *panel = &connector->panel;
 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
 
+	if (!panel->backlight.edp.vesa.info.aux_enable) {
+		u32 pwm_level = intel_backlight_invert_pwm_level(connector,
+								 panel->backlight.pwm_level_max);
+
+		panel->backlight.pwm_funcs->enable(crtc_state, conn_state, pwm_level);
+	}
+
 	drm_edp_backlight_enable(&intel_dp->aux, &panel->backlight.edp.vesa.info, level);
 }
 
@@ -304,6 +311,10 @@ static void intel_dp_aux_vesa_disable_backlight(const struct drm_connector_state
 	struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder);
 
 	drm_edp_backlight_disable(&intel_dp->aux, &panel->backlight.edp.vesa.info);
+
+	if (!panel->backlight.edp.vesa.info.aux_enable)
+		panel->backlight.pwm_funcs->disable(old_conn_state,
+						    intel_backlight_invert_pwm_level(connector, 0));
 }
 
 static int intel_dp_aux_vesa_setup_backlight(struct intel_connector *connector, enum pipe pipe)
@@ -321,6 +332,15 @@ static int intel_dp_aux_vesa_setup_backlight(struct intel_connector *connector,
 	if (ret < 0)
 		return ret;
 
+	if (!panel->backlight.edp.vesa.info.aux_enable) {
+		ret = panel->backlight.pwm_funcs->setup(connector, pipe);
+		if (ret < 0) {
+			drm_err(&i915->drm,
+				"Failed to setup PWM backlight controls for eDP backlight: %d\n",
+				ret);
+			return ret;
+		}
+	}
 	panel->backlight.max = panel->backlight.edp.vesa.info.max;
 	panel->backlight.min = 0;
 	if (current_mode == DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD) {
@@ -340,12 +360,7 @@ intel_dp_aux_supports_vesa_backlight(struct intel_connector *connector)
 	struct intel_dp *intel_dp = intel_attached_dp(connector);
 	struct drm_i915_private *i915 = dp_to_i915(intel_dp);
 
-	/* 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_BACKLIGHT_AUX_ENABLE_CAP) &&
-	    drm_edp_backlight_supported(intel_dp->edp_dpcd)) {
+	if (drm_edp_backlight_supported(intel_dp->edp_dpcd)) {
 		drm_dbg_kms(&i915->drm, "AUX Backlight Control Supported!\n");
 		return true;
 	}