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

From: Stephen Boyd
Date: Wed May 10 2023 - 18:47:07 EST


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@xxxxxxxxxxx>
> ---

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?