Re: [PATCH 07/13] drm/msm/dp: Track validity of cached sink link capabilities

[Dmitry Baryshkov]

On Wed, Sep 30, 2026 at 08:41:51PM +0800, Xilin Wu wrote:
> An eDP panel may not have been powered up when its mode is checked, and a
> disconnected DP sink can leave cached link capabilities behind. The cached
> values alone do not distinguish either case from a current read.

Since eDP caps (hopefully) don't change, would it be better to cache
them on the first access?

> 
> Track whether link capability discovery completed successfully. Clear the
> flag before reading capabilities and on unplug, and set it only after the
> downstream information has been read successfully. Subsequent atomic
> checks can then defer checks against unknown capabilities until the sink
> is accessible.
> 
> Assisted-by: LLM
> Signed-off-by: Xilin Wu <sophon@xxxxxxxxx>
> ---
>  drivers/gpu/drm/msm/dp/dp_display.c | 1 +
>  drivers/gpu/drm/msm/dp/dp_panel.c   | 3 +++
>  drivers/gpu/drm/msm/dp/dp_panel.h   | 1 +
>  3 files changed, 5 insertions(+)
> 

-- 
With best wishes
Dmitry