ACK/Cmnt: [SRU][R][PATCH 0/1] drm/i915: Restore VESA backlight interface

[Tim Whisonant]

On Mon, Jul 27, 2026 at 05:21:37PM +0200, Krystian Kaniewski via kernel-team wrote:
> BugLink: https://bugs.launchpad.net/bugs/2161309
> 
> SRU Justification:
> 
> [Impact]
> 
> Ubuntu kernel 7.0.0-28.28 includes commit 40d2f5820951
> ("drm/i915/backlight: Remove try_vesa_interface").
> 
> That change causes an internal display backlight regression on systems
> whose panel advertises VESA AUX backlight support but actually requires
> the Intel/PWM backlight path. Brightness writes complete and the value
> under /sys/class/backlight/intel_backlight changes, but the physical
> screen brightness does not change.
> 
> [Fix]
> 
> Cherry-pick upstream commit:
> 
> f30fddb44023 ("Revert \"drm/i915/backlight: Remove try_vesa_interface\"")
> 
> This reverts commit:
> 
> 40d2f5820951 ("drm/i915/backlight: Remove try_vesa_interface")
> 
> The revert restores the try_vesa_interface gate. This prevents i915
> from selecting the VESA AUX backlight path as an unconditional fallback
> on panels whose VBT indicates that the Intel backlight interface should
> be used.
> 
> [Test Case]
> 
> Build tested
> 
> [Where problems could occur]
> 
> The change affects the i915 backlight interface-selection logic for
> internal eDP displays.
> 
> A regression could cause brightness control to stop working, select an
> incorrect backlight interface, or restore the wrong brightness level
> after suspend and resume.
> 
> The regression potential is considered limited because an equivalent
> change has already been merged and reviewed upstream.
> 
> [Other Info]
> 
> The upstream revert is present as f30fddb44023. An equivalent
> cherry-pick, 2914709c9141, was included before Linux 7.1-rc7.
> 
> Suraj Kandpal (1):
>   Revert "drm/i915/backlight: Remove try_vesa_interface"
> 
>  .../drm/i915/display/intel_dp_aux_backlight.c | 19 ++++++++++++-------
>  1 file changed, 12 insertions(+), 7 deletions(-)
> 
> -- 
> 2.53.0
> 

Patch Applier,

Please add the Buglink to the top of the patch when applying it.

Thanks,
Tim


Acked-by: Tim Whisonant <tim.whisonant at canonical.com>