linux-kernel - Re: [PATCH 03/15] drm/panfrost: don't use pfdevfreq.busy

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Date:   Thu, 28 May 2020 14:22:38 +0100
From:   Steven Price <steven.price@....com>
To:     Clément Péron <peron.clem@...il.com>,
        Rob Herring <robh@...nel.org>,
        Tomeu Vizoso <tomeu.vizoso@...labora.com>,
        Alyssa Rosenzweig <alyssa.rosenzweig@...labora.com>,
        Viresh Kumar <vireshk@...nel.org>, Nishanth Menon <nm@...com>,
        Stephen Boyd <sboyd@...nel.org>,
        Maxime Ripard <mripard@...nel.org>,
        Chen-Yu Tsai <wens@...e.org>
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 03/15] drm/panfrost: don't use pfdevfreq.busy_count to
 know if hw is idle

On 10/05/2020 17:55, Clément Péron wrote:
> This use devfreq variable that will be lock with spinlock in future
> patches. We should either introduce a function to access this one
> but as devfreq is optional let's just remove it.
> 
> Signed-off-by: Clément Péron <peron.clem@...il.com>

As far as I can tell this should be safe. As you note this wouldn't work 
without devfreq anyway.

Reviewed-by: Steven Price <steven.price@....com>

> ---
>   drivers/gpu/drm/panfrost/panfrost_job.c | 4 ----
>   1 file changed, 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 7914b1570841..63e32a9f2749 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -581,10 +581,6 @@ int panfrost_job_is_idle(struct panfrost_device *pfdev)
>   	struct panfrost_job_slot *js = pfdev->js;
>   	int i;
>   
> -	/* Check whether the hardware is idle */
> -	if (atomic_read(&pfdev->devfreq.busy_count))
> -		return false;
> -
>   	for (i = 0; i < NUM_JOB_SLOTS; i++) {
>   		/* If there are any jobs in the HW queue, we're not idle */
>   		if (atomic_read(&js->queue[i].sched.hw_rq_count))
>