On Thu, 16 Jul 2026, Suraj Kandpal wrote:
Turns out Some panels allow only backlight AUX based backlight
nits:
s/Some/some/
s/backlight AUX/AUX/
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, specially ones with no PWM controller.
maybe: s/specially/especially/
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 <[email protected]>
---
drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 3 +--
1 file changed, 1 insertion(+), 2 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 7a6c07f6aaeb..83245cb738e5 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -619,8 +619,7 @@ check_if_vesa_backlight_possible(struct intel_dp *intel_dp)
* Since we only support Fully AUX Based VESA Backlight interface make
sure
* backlight enable is possible via AUX along with backlight adjustment
*/
Wondering if the comment above needs any adjustment?
Either way:
Reviewed-by: Michał Grzelak <[email protected]>
BR,
Michał
- 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);
