Hi all, On Fri, Jul 10, 2026 at 03:31:08PM +0300, Ilpo Järvinen wrote: > On Fri, 10 Jul 2026, Denis Benato wrote: > > On 7/9/26 22:08, Salvatore Bonaccorso wrote: > > > Control: forwarded -1 > > > https://lore.kernel.org/regressions/[email protected] > > > 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: [email protected] > > >> > > >> 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? > > Hi Salvatore, > > > > The commit incriminated is this one: > > https://lore.kernel.org/all/[email protected]/ > > > > As you can see that commit changes min/max of the brightness range, but > > does not touch the detection at all, > > To be more precise, it DOES change read_screenpad_backlight_power() -> > asus_wmi_get_devstate_simple() but AFAICT that cannot make things worse > because asus_wmi_get_devstate_simple() used in both cases, so I was > left to wonder the same thing as you. > > That being said, it's hard to see how bisect could point this to a wrong > commit either because good/bad should be pretty obvious. > > Did reverting the suspect commit on top of 6.12.94 result in a working > system?
Ponali did test, and reported back in the Debian bug at https://bugs.debian.org/1141604#60, quoting: > I have found the sysfs attribute for brightness control to be in > /sys/class/backlight/asus_screenpad, and it appears on both 6.12.90 and > 6.12.94. > > On 6.12.90, max_brightness reports 235. > > On 6.12.94, max_brightness reports 255. > > > I have checked out to v6.12.94, reverted the suspect commit, and found > the ScreenPad to be working as intended. > > > Regards, > > Ponali Regards, Salvatore
