[Freedreno] [PATCH v2] drm/msm/dpu: handle pm_runtime_get_sync() errors in bind path

[Abhinav Kumar]

On 5/18/2022 5:40 PM, Stephen Boyd wrote:
> Quoting Abhinav Kumar (2022-05-18 15:34:07)
>> If there are errors while trying to enable the pm in the
>> bind path, it will lead to unclocked access of hw revision
>> register thereby crashing the device.
>>
>> This will not address why the pm_runtime_get_sync() fails
>> but at the very least we should be able to prevent the
>> crash by handling the error and bailing out earlier.
>>
>> changes in v2:
>>          - use pm_runtime_resume_and_get() instead of
>>            pm_runtime_get_sync()
>>
>> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
>> ---
> 
> Any Fixes tag? When did pm errors start happening in the bind path?
> 
> Reviewed-by: Stephen Boyd <swboyd at chromium.org>

This error got exposed with PANEL_EDP=m and DRM_MSM=y. We were not 
testing this combination previously. This combination causes "clk stuck 
at OFF" from the pm_runtime_get_sync() path which means we shouldnt 
proceed with the next register access since it failed.

We are still debugging the root-cause of why "clk stuck at OFF" error is 
present, this is just resolving the crash.

Fixes : 25fdd5933e4c ("drm/msm: Add SDM845 DPU support")