Re: [PATCH v3 1/2] platform/x86: asus-wmi: adjust screenpad power/brightness handling — regression on non-DUO ScreenPad (ASUS ZenBook UX435EG)

[Denis Benato]

On 8/1/26 20:03, Manuel A. R. de Orúe Ríos wrote:
> Hi Denis, Luke,
>
> I'm following up on this patch series (commit 034f5efd362fb87a3970d61eaf982664f84e6c5a,
> merged for kernel 7.0.10) — I believe I've found and confirmed a regression it
> introduces on non-DUO ScreenPad hardware.
>
> Hardware: ASUS ZenBook UX435EG (BIOS UX435EG.315), single ScreenPad model
> (not ScreenPad Plus / DUO).
>
> Symptom: after upgrading past kernel-7.0.9-205 to kernel-7.0.10-200 (and
> confirmed still present in 7.1.5), the ScreenPad stops functioning as a
> secondary display entirely — it still works as a touchpad (separate i2c-hid
> digitizer), but the panel itself never lights up as a screen.
>
> I bisected this cleanly across official Fedora kernel builds:
>   kernel-7.0.9-205.fc44   -> works
>   kernel-7.0.10-200.fc44  -> broken
>   kernel-7.1.5-201.fc44   -> still broken
>
>
> image.png
> I understand from the review thread that this series was tested specifically
> on a ZenBook DUO — it's very possible the DUO's ScreenPad firmware/EC
> behaves differently enough that the polarity works out correctly there, while
> it's inverted on this single-ScreenPad model.
>
> Happy to test any proposed fix on this hardware, or provide more DMI/ACPI/
> debug info if useful. I'm currently working around this with a udev-triggered
> script forcing bl_power=4 on boot, but would obviously prefer a proper fix.
>
> Kernel/hardware details:
> DMI: ASUSTeK COMPUTER INC. ZenBook UX435EG_UX435EG/UX435EG, BIOS UX435EG.315 04/22/2022
> Distro: Fedora Linux 44 (KDE Plasma)
>
> Thanks for the work on this — I know these ScreenPad quirks are a pain to
> get right across the different hardware variants.
>
> Best,
> ___________________________


Please try the below patch and see if it fixes things for you: