Date: Wed, 26 Oct 2016 19:43:57 -0200
From: Gustavo Padovan <gustavo@padovan.org>
To: Brian Starkey <brian.starkey@arm.com>
Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org
Subject: Re: [RFC PATCH v2 9/9] drm: mali-dp: Add writeback out-fence support
Message-ID: <20161026214357.GH12629@joana>
Mail-Followup-To: Gustavo Padovan <gustavo@padovan.org>,
        Brian Starkey <brian.starkey@arm.com>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        linux-media@vger.kernel.org
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 <1477472108-27222-10-git-send-email-brian.starkey@arm.com>
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2016-10-26 Brian Starkey <brian.starkey@arm.com>:

> If userspace has asked for an out-fence for the writeback, we add a
> fence to malidp_mw_job, to be signaled when the writeback job has
> completed.
> 
> Signed-off-by: Brian Starkey <brian.starkey@arm.com>
> ---
>  drivers/gpu/drm/arm/malidp_hw.c |    5 ++++-
>  drivers/gpu/drm/arm/malidp_mw.c |   18 +++++++++++++++++-
>  drivers/gpu/drm/arm/malidp_mw.h |    3 +++
>  3 files changed, 24 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/arm/malidp_hw.c b/drivers/gpu/drm/arm/malidp_hw.c
> index 1689547..3032226 100644
> --- a/drivers/gpu/drm/arm/malidp_hw.c
> +++ b/drivers/gpu/drm/arm/malidp_hw.c
> @@ -707,8 +707,11 @@ static irqreturn_t malidp_se_irq(int irq, void *arg)
>  		unsigned long irqflags;
>  		/*
>  		 * We can't unreference the framebuffer here, so we queue it
> -		 * up on our threaded handler.
> +		 * up on our threaded handler. However, signal the fence
> +		 * as soon as possible
>  		 */
> +		malidp_mw_job_signal(drm, malidp->current_mw, 0);

Drivers should not deal with fences directly. We need some sort of 
drm_writeback_finished() that will do the signalling for you.

Gustavo