[PATCH] Revert "drm/msm/dp: use drm_bridge_hpd_notify() to report HPD status changes"

[Johan Hovold]

On Wed, Feb 28, 2024 at 12:08:08AM +0200, Dmitry Baryshkov wrote:
> This reverts commit e467e0bde881 ("drm/msm/dp: use
> drm_bridge_hpd_notify() to report HPD status changes").
> 
> The commit changed the way how the MSM DP driver communicates
> HPD-related events to the userspace. The mentioned commit made some of
> the HPD events being reported earlier. This way userspace starts poking
> around. It interacts in a bad way with the dp_bridge_detect and the
> driver's state machine, ending up either with the very long delays
> during hotplug detection or even inability of the DP driver to report
> the display as connected.
> 
> A proper fix will involve redesigning of the HPD handling in the MSM DP
> driver. It is underway, but it will be intrusive and can not be thought
> about as a simple fix for the issue. Thus, revert the offending commit.
> 
> Fixes: e467e0bde881 ("drm/msm/dp: use drm_bridge_hpd_notify() to report HPD status changes")
> Link: https://gitlab.freedesktop.org/drm/msm/-/issues/50
> Reported-by: Johan Hovold <johan at kernel.org>
> Link: https://lore.kernel.org/r/Zd3YPGmrprxv-N-O@hovoldconsulting.com/
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>

Tested-by: Johan Hovold <johan+linaro at kernel.org>