This reverts commit 40d2f5820951dee818d05c14677277048bd85f9f. Removing the try_vesa_interface gate caused a backlight regression on panels whose VBT correctly reports INTEL_BACKLIGHT_DISPLAY_DDI and whose PWM path is the actual backlight control, but whose DPCD optimistically advertises DP_EDP_BACKLIGHT_AUX_ENABLE_CAP / _BRIGHTNESS_AUX_SET_CAP. After the commit such panels silently bind to the VESA AUX backlight funcs; AUX writes complete but the panel ignores them, leaving brightness stuck (no-op backlight). Observed on at least KBL and TGL eDP setups.
Signed-off-by: Suraj Kandpal <[email protected]> --- .../drm/i915/display/intel_dp_aux_backlight.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) 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 a8d56ebf06a2..7a6c07f6aaeb 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c @@ -691,10 +691,9 @@ int intel_dp_aux_init_backlight_funcs(struct intel_connector *connector) struct intel_dp *intel_dp = intel_attached_dp(connector); struct drm_device *dev = connector->base.dev; struct intel_panel *panel = &connector->panel; - bool try_intel_interface = false; + bool try_intel_interface = false, try_vesa_interface = false; - /* - * Check the VBT and user's module parameters to figure out which + /* Check the VBT and user's module parameters to figure out which * interfaces to probe */ switch (display->params.enable_dpcd_backlight) { @@ -703,6 +702,7 @@ int intel_dp_aux_init_backlight_funcs(struct intel_connector *connector) case INTEL_DP_AUX_BACKLIGHT_AUTO: switch (panel->vbt.backlight.type) { case INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE: + try_vesa_interface = true; break; case INTEL_BACKLIGHT_DISPLAY_DDI: try_intel_interface = true; @@ -715,12 +715,20 @@ int intel_dp_aux_init_backlight_funcs(struct intel_connector *connector) if (panel->vbt.backlight.type != INTEL_BACKLIGHT_VESA_EDP_AUX_INTERFACE) try_intel_interface = true; + try_vesa_interface = true; + break; + case INTEL_DP_AUX_BACKLIGHT_FORCE_VESA: + try_vesa_interface = true; break; case INTEL_DP_AUX_BACKLIGHT_FORCE_INTEL: try_intel_interface = true; break; } + /* For eDP 1.5 and above we are supposed to use VESA interface for brightness control */ + if (intel_dp->edp_dpcd[0] >= DP_EDP_15) + try_vesa_interface = true; + /* * Since Intel has their own backlight control interface, the majority of machines out there * using DPCD backlight controls with Intel GPUs will be using this interface as opposed to @@ -733,9 +741,6 @@ int intel_dp_aux_init_backlight_funcs(struct intel_connector *connector) * panel with Intel's OUI - which is also required for us to be able to detect Intel's * backlight interface at all. This means that the only sensible way for us to detect both * interfaces is to probe for Intel's first, and VESA's second. - * - * Also there is a chance some VBTs may advertise false Intel backlight support even if the - * TCON DPCD says otherwise. This means we keep VESA interface as fallback in that case. */ if (try_intel_interface && intel_dp->edp_dpcd[0] <= DP_EDP_14b && intel_dp_aux_supports_hdr_backlight(connector)) { @@ -745,7 +750,7 @@ int intel_dp_aux_init_backlight_funcs(struct intel_connector *connector) return 0; } - if (intel_dp_aux_supports_vesa_backlight(connector)) { + if (try_vesa_interface && intel_dp_aux_supports_vesa_backlight(connector)) { drm_dbg_kms(dev, "[CONNECTOR:%d:%s] Using VESA eDP backlight controls\n", connector->base.base.id, connector->base.name); panel->backlight.funcs = &intel_dp_vesa_bl_funcs; -- 2.34.1
