Re: [PATCH v2] platform/loongarch: laptop: explicitly reset the bl_powered state when resuming

[Yao Zi]

On Thu, Jul 23, 2026 at 08:18:39PM +0800, Zixing Liu wrote:
> On EAECIS NL60R with EC firmware version 1.11, resuming from S3 has a very
> high chance (>= 90%) of causing the EC to lose the previous backlight
> power state. When this happens, the laptop resumes normally from S3, but
> the backlight remains off (when shining on the screen with a flash light,
> we can see the screen contents are updating normally).
> 
> Since there is no generic way to query the EC's backlight state on
> Loongson laptop platforms, assume the worst-case scenario and restart the
> backlight power inside the kernel each time the system resumes.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 53c762b47f72 ("platform/loongarch: laptop: Add backlight power control support")
> Signed-off-by: Zixing Liu <liushuyu@xxxxxxx>
> ---
> Changes in v2:
> - Move bl_powered reset logic to loongson_hotkey_suspend.
> - Link to v1: https://lore.kernel.org/loongarch/20260722044457.1333404-1-liushuyu@xxxxxxx/

Again on my TongFang L860-T2 3A5000 laptop, no regression is observed.

Tested-by: Yao Zi <me@xxxxxxxx>

Best regards.
Yao Zi