[PATCH v1 2/2] drm/msm/dp: add mutex to protect internal_hpd against race condition between different threads

[Abhinav Kumar]

On 5/10/2023 3:46 PM, Stephen Boyd wrote:
> Quoting Kuogee Hsieh (2023-05-10 13:31:05)
>> Intrenal_hpd is referenced by event thread but set by drm bridge callback
>> context. Add mutex to protect internal_hpd to avoid conflicts between
>> threads.
>>
>> Signed-off-by: Kuogee Hsieh <quic_khsieh at quicinc.com>
>> ---
> 
> This patch looks completely unnecessary. How can dp_bridge_hpd_enable()
> be called at the same time that dp_bridge_hpd_disable() is called or
> dp_bridge_hpd_notify() is called? Isn't there locking or ordering at a
> higher layer?

Ack. We can drop this patch because we are protected by 
bridge->hpd_mutex in drm_bridge_hpd_enable() / drm_bridge_hpd_disable () 
and drm_bridge_hpd_notify().