[Intel-gfx] [PATCH] drm/i915: Serialise i915_active_wait() with its retirement

[Tvrtko Ursulin]

On 29/11/2019 09:39, Chris Wilson wrote:
> As the i915_active.retire() may be running on another CPU as we detect
> that the i915_active is idle, we may not wait for the retirement itself.
> Wait for the remote callback by waiting for the retirement worker.
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=112424
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>   drivers/gpu/drm/i915/i915_active.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
> index 479195ecbc6c..e8630ee33336 100644
> --- a/drivers/gpu/drm/i915/i915_active.c
> +++ b/drivers/gpu/drm/i915/i915_active.c
> @@ -469,6 +469,7 @@ int i915_active_wait(struct i915_active *ref)
>   	if (wait_var_event_interruptible(ref, i915_active_is_idle(ref)))
>   		return -EINTR;
>   
> +	flush_work(&ref->work);
>   	return 0;
>   }
>   
> 

Hm, but wake_up_war is in the worker so how does wait_var_event wake the 
waiter up before it has been retired?

Regards,

Tvrtko