FAILED: patch "[PATCH] drm/i915: Add support for panels with VESA backlights with" 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 ------------------

From 61e29a0956bdb09eac8aca7d9add9f902baff08b Mon Sep 17 00:00:00 2001
From: Lyude Paul <[email protected]>
Date: Fri, 5 Nov 2021 14:33:38 -0400
Subject: [PATCH] drm/i915: Add support for panels with VESA backlights with PWM enable/disable
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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 <[email protected]>

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 <[email protected]>

Cc <[email protected]> # v5.12+

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

(cherry picked from commit 04f0d6cc62cc1eaf9242c081520c024a17ba86a3)

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

drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c +0 -0

index 569d17b4d00f..f05b71c01b8e 100644
@@ -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-

Quoted 1 line

backlight.pwm_level_max);

+
+               panel->backlight.pwm_funcs->enable(crtc_state, conn_state, pwm_level);
+       }
+
        drm_edp_backlight_enable(&intel_dp->aux, &panel-

Quoted 1 line

backlight.edp.vesa.info, level);

 }

drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c +0 -0

@@ -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-

Quoted 1 line

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)

drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c +0 -0

@@ -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) {

drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c +0 -0

@@ -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;
        }

Huh, well this is strange. I'm assuming that you send these emails out as part of an automated script that tries applying patches and fails, but I think something may have gone wrong here as I just tried cherry-picking 04f0d6cc62cc1eaf9242c081520c024a17ba86a3 onto v5.15.6, and it applied without needing any manual conflict resolution. Any idea what might be going on?

Quoted 7 lines · Lyude Paul

Huh, well this is strange. I'm assuming that you send these emails out as part
of an automated script that tries applying patches and fails, but I think something may have gone wrong here as I just tried cherry-picking 04f0d6cc62cc1eaf9242c081520c024a17ba86a3 onto v5.15.6, and it applied without
needing any manual conflict resolution. Any idea what might be going on?

You mean 61e29a0956bd ("drm/i915: Add support for panels with VESA backlights with PWM enable/disable"), right?

Anyway, yes, it fails to build:

  CC [M]  drivers/gpu/drm/i915/display/intel_dp_aux_backlight.o drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c: In function ‘intel_dp_aux_vesa_enable_backlight’:
drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c:302:33: error:
implicit declaration of function ‘intel_backlight_invert_pwm_level’; did you mean ‘intel_panel_invert_pwm_level’? [-Werror=implicit-function-declaration] 302 |                 u32 pwm_level = intel_backlight_invert_pwm_level(connector,
      |                                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |                                 intel_panel_invert_pwm_level
cc1: all warnings being treated as errors

thanks,

greg k-h