Re: [PATCH v13 3/4] drm/atomic-helper: Re-order bridge chain pre-enable and post-disable

Aradhya Bhatia
2025-10-06T15:30:53Z

+rockchip maintainers

Hi Vicente, all,

I went through the drivers and the affected areas in the gru-kevin
chromebook pipeline last week, but nothing has stood out.

Pipeline:

rockchip,display-subsystem / rk3399-vop (Big/Lite) (CRTC) ->
rk3399-edp (Encoder) -> analogix_dp_core (Bridge) ->
sharp,lq123p (edp-panel)

I am unable to debug this further since I do not have the hardware.

I could use some help, especially from folks who understand the hardware
requirements better.

On 11/09/25 09:01, Aradhya Bhatia wrote:
> Hi Vicente,
>
> Thank you for the bisection and reporting the issue.
>
> On 10/09/25 16:17, Vicente Bergas wrote:
>> Hi,
>> this patch causes a regression. It has been reported in
>> https://bugzilla.kernel.org/show_bug.cgi?id=220554
>>
>> It affects the gru/kevin platform (arm64,RK3399) with the Panfrost DRM driver.
>
> I believe the Panfrost DRM driver may only be for the GPU.
>
> Based on the dts files in arm64/rockchip/, this is the pipeline of the
> gru-kevin setup that I understand.
>
> rk3399-vop (Big/Lite) -> rk3399-edp -> sharp,lq123p (edp-panel)
>
> The setup seems to be using the drm/rockchip drivers for the display
> controller and for the bridge.
>
>>
>> When it boots in console mode, the blinking of the cursor keeps the display on.
>> If it is turned off via /sys/class/graphics/fbcon/cursor_blink, then
>> the display briefly shows each key press presented on screen for less
>> than one second and then powers off.
>>
>> When starting the graphical mode (wayland), if there are no
>> applications drawing on the screen, the only way to keep the display
>> on is by continuously moving the mouse.
>>
>
> Okay!
>
> I will have a look through the drivers. In the meanwhile, please do
> report back if you find any other observations.
>
>

--
Regards
Aradhya