Re: Bug#1141604: linux-image-6.12.94+deb13-amd64: does not detect ScreenPad on ASUS VivoBook

[Salvatore Bonaccorso <carnil@debian.org>]

Control: forwarded -1 https://lore.kernel.org/regressions/178362762638.911488.8564892548331679884@eldamar.lan
Control: tags -1 + upstream

Hi,

Ponali reported in Debian (https://bugs.debian.org/1141604) the
following issue after updating from 6.12.90 to 6.12.94. First quoting
the report:

On Tue, Jul 07, 2026 at 07:37:24AM +0200, Ponali wrote:
> Package: src:linux
> Version: 6.12.94-1
> Severity: normal
> Tags: upstream, regression
> X-Debbugs-Cc: ponali2k@gmail.com
> 
> Last known working kernel: 6.12.90-1
> First known broken kernel: 6.12.94-1
> 
> 
> Dear Maintainer,
> 
> I upgraded all my packages through apt, which also upgraded the linux image
> from 6.12.90 to 6.12.94.
> 
> I expected the ScreenPad display to continue to be detected and exposed as a
> DRM output, like on 6.12.90. The ScreenPad being the trackpad with a screen,
> which came with my computer (ASUS VivoBook X532FA_S532FA).
> 
> After upgrading and rebooting, the new kernel caused a regression where the
> display of the ScreenPad fails to get recognized by the kernel. The touchpad
> functionality still works. Usually, the ScreenPad would appear as "HDMI-A-1".
> The DRM connector for it still exists (/sys/class/drm/card0-HDMI-A-1), but
> "status" reports "disabled"
> 
> I could not get the ScreenPad display to be recognized again on the new kernel,
> so I configured GRUB to automatically boot to the 6.12.90 kernel through the
> "Advanced Options". The ScreenPad is recognized on older kernel versions, so I
> am still able to use it (until a new LPE comes around).
> 
> To replicate:
> 1. Boot with 6.12.90. The ScreenPad display is detected as HDMI-A-1.
> 2. Boot with 6.12.94 with the exact same hardware.
> 3. The ScreenPad display is no longer usable.
> 
> 
> My main display is eDP-1 (1920x1080), though it isn't essential. My GPU is an
> integrated Intel iGPU, and the driver used for both screens is i915. I have
> booted to the new kernel for reportbug to get all the information
> automatically, but i will continue to use the old one until the appropriate
> time.

Now, Ponali did bisect the changes between 6.12.90 and 6.12.94 and
found that the backport of the commit 8d95d1f4aa5c ("platform/x86:
asus-wmi: fix screenpad brightness range") changed the behaviour.
Bisect log is at: https://bugs.debian.org/1141604#22

As this change was backported to other stable series as well I asked
Ponali to please test 7.0.y and 7.1.y and confirmed that both 7.0.13
and as well 7.1.3 show the hehaviour.

#regzbot introduced: 8d95d1f4aa5c76202b0833a70998769384612488
#regzbot link: https://bugs.debian.org/1141604

Is there anything Ponali can report back to further debug the issue?

Regards,
Salvatore