[PATCH v2 4/4] drm/bridge: ti-sn65dsi86: Update reply on aux failures

[Doug Anderson]

Hi,

On Thu, Oct 29, 2020 at 6:17 PM Stephen Boyd <swboyd at chromium.org> wrote:
>
> We should be setting the drm_dp_aux_msg::reply field if a NACK or a
> SHORT reply happens. Update the error bit handling logic in
> ti_sn_aux_transfer() to handle these cases and notify upper layers that
> such errors have happened. This helps the retry logic understand that a
> timeout has happened, or to shorten the read length if the panel isn't
> able to handle the longest read possible.
>
> Note: I don't have any hardware that exhibits these code paths so this
> is written based on reading the datasheet for this bridge and inspecting
> the code and how this is called.
>
> Changes in v2:
>  - Handle WRITE_STATUS_UPDATE properly
>
> Cc: Douglas Anderson <dianders at chromium.org>
> Cc: Laurent Pinchart <Laurent.pinchart at ideasonboard.com>
> Cc: Jonas Karlman <jonas at kwiboo.se>
> Cc: Jernej Skrabec <jernej.skrabec at siol.net>
> Cc: Sean Paul <seanpaul at chromium.org>
> Signed-off-by: Stephen Boyd <swboyd at chromium.org>
> ---
>  drivers/gpu/drm/bridge/ti-sn65dsi86.c | 36 ++++++++++++++++++++++++---
>  1 file changed, 32 insertions(+), 4 deletions(-)

This looks right to me, now.  Hopefully if/when someone ends up with
hardware that exercises these codepaths they'll at least be in a
better state and maybe they will all just work!  :-)

Reviewed-by: Douglas Anderson <dianders at chromium.org>