From: Suraj Kandpal Date: Thu, 16 Jul 2026 03:09:59 +0000 (+0530) Subject: drm/i915/backlight: Remove DP_EDP_BACKLIGHT_AUX_ENABLE_CAP check for DPCD backlight X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=a411ea4a87162898d2a0547fdfb721ddb7626be3;p=thirdparty%2Fkernel%2Flinux.git drm/i915/backlight: Remove DP_EDP_BACKLIGHT_AUX_ENABLE_CAP check for DPCD backlight Turns out some panels allow only AUX based backlight by just setting the DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP and not setting the DP_EDP_BACKLIGHT_AUX_ENABLE_CAP. If we make DP_EDP_BACKLIGHT_AUX_ENABLE_CAP a necessity for AUX based DPCD backlight these panels loose the ability to manipulate backlight via AUX, especially ones with no PWM controller. Remove this check from function so that panels who do not advertise DP_EDP_BACKLIGHT_AUX_ENABLE_CAP but advertise DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP are able to manipulate backlight again. Fixes: ed8be780bdbc ("drm/i915/backlight: Fix VESA backlight possible check condition") Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/work_items/16507 Signed-off-by: Suraj Kandpal Reviewed-by: Michał Grzelak Link: https://patch.msgid.link/20260716030959.436430-1-suraj.kandpal@intel.com (cherry picked from commit 7d594b24c915afb4b0c5fb8875403253daef5b24) Signed-off-by: Rodrigo Vivi --- 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 7a6c07f6aaeb..266e042e0023 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c @@ -615,12 +615,7 @@ check_if_vesa_backlight_possible(struct intel_dp *intel_dp) int ret; u8 bit_min, bit_max; - /* - * Since we only support Fully AUX Based VESA Backlight interface make sure - * backlight enable is possible via AUX along with backlight adjustment - */ - if (!(intel_dp->edp_dpcd[1] & DP_EDP_BACKLIGHT_AUX_ENABLE_CAP && - intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP)) + if (!(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP)) return false; ret = drm_dp_dpcd_read_byte(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN, &bit_min);