Re: [PATCH v2] drm/msm/dsi: skip the wait for video mode done if not applicable

From: Dmitry Baryshkov
Date: Fri Sep 15 2023 - 20:32:49 EST


On Fri, 15 Sept 2023 at 23:45, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
>
> dsi_wait4video_done() API waits for the DSI video mode engine to
> become idle so that we can transmit the DCS commands in the
> beginning of BLLP. However, with the current sequence, the MDP
> timing engine is turned on after the panel's pre_enable() callback
> which can send out the DCS commands needed to power up the panel.
>
> During those cases, this API will always timeout and print out the
> error spam leading to long bootup times and log flooding.
>
> Fix this by checking if the DSI video engine was actually busy before
> waiting for it to become idle otherwise this is a redundant wait.
>
> changes in v2:
> - move the reg read below the video mode check
> - minor fixes in commit text
>
> Closes: https://gitlab.freedesktop.org/drm/msm/-/issues/34
> Fixes: a689554ba6ed ("drm/msm: Initial add DSI connector support")
> Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>

> ---
> drivers/gpu/drm/msm/dsi/dsi_host.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>


--
With best wishes
Dmitry