[Intel-gfx] [PATCH 09/17] drm/i915: Wait until the intel_wakeref idle callback is complete

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> When waiting for idle, serialise with any ongoing callback so that it
> will have completed before completing the wait.

Might be come apparent and evident when reading the patch
that introduce the intel_wakeref_unlock_wait(),
but reader is yearning for a why part.

The 'wait_for_idle' is kind of revaling of
why the need for sync tho.

-Mika

>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/intel_wakeref.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_wakeref.c b/drivers/gpu/drm/i915/intel_wakeref.c
> index 9b29176cc1ca..91feb53b2942 100644
> --- a/drivers/gpu/drm/i915/intel_wakeref.c
> +++ b/drivers/gpu/drm/i915/intel_wakeref.c
> @@ -109,8 +109,15 @@ void __intel_wakeref_init(struct intel_wakeref *wf,
>  
>  int intel_wakeref_wait_for_idle(struct intel_wakeref *wf)
>  {
> -	return wait_var_event_killable(&wf->wakeref,
> -				       !intel_wakeref_is_active(wf));
> +	int err;
> +
> +	err = wait_var_event_killable(&wf->wakeref,
> +				      !intel_wakeref_is_active(wf));
> +	if (err)
> +		return err;
> +
> +	intel_wakeref_unlock_wait(wf);
> +	return 0;
>  }
>  
>  static void wakeref_auto_timeout(struct timer_list *t)
> -- 
> 2.24.0