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

[Paloma Arellano]

On 2/27/2024 2:11 PM, Abhinav Kumar wrote:
>
>
> On 2/27/2024 2:08 PM, 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.
>>
>
> Yes, for fixing this on 6.9 I am fine with this.
>
> I hope there were not other changes which were built on top of this. 
> So it will be better if we retest internal HPD case as well with this.
>
> We will do that in a day or two and give Tested-by.
>
>> 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>
>> ---
>>   drivers/gpu/drm/msm/dp/dp_display.c | 20 ++++++++++++++++++--
>>   1 file changed, 18 insertions(+), 2 deletions(-)
>>
>
> For the change itself,
>
>
> Reviewed-by: Abhinav Kumar <quic_abhinavk at quicinc.com>


Tested-by: Paloma Arellano <quic_parellan at quicinc.com>