Skip to content

Backlight no longer working on Asus t100ta since kernel 6.1

Backlight no longer works on Asus T100TA since 6.1 kernels. Last kernel with backlight working for me is on kernel 6.0.9. I suggest the relevant error in kernel log is:

i915 0000:00:02.0: cannot find GPIO chip gpio_crystalcove, deferring
i915 0000:00:02.0: [drm] *ERROR* Failed to own gpio for panel control
i915 0000:00:02.0: [drm] *ERROR* [CONNECTOR:86:DSI-1] Failed to get the PMIC PWM chip

I suspect the whole issue is connected with backlight detection subsystem revision that occured somewhere around kernel 6.1. My /sys/class/backlight/ path shows intel_backlight symlink on working 6.0.9 kernel. On 6.1 and newer it shows two acpi_video nodes. I'm happy to provide any further logs or dumps.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information