linux-kernel - Re: [PATCH] [v2] drm/panfrost: Fix runtime PM imbalance on error

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Message-ID: <48348af2-649c-7305-6255-6ae6a80e9b7a@arm.com>
Date:   Wed, 27 May 2020 16:52:03 +0100
From:   Steven Price <steven.price@....com>
To:     Dinghao Liu <dinghao.liu@....edu.cn>, kjlu@....edu
Cc:     Rob Herring <robh@...nel.org>,
        Tomeu Vizoso <tomeu.vizoso@...labora.com>,
        Alyssa Rosenzweig <alyssa.rosenzweig@...labora.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [v2] drm/panfrost: Fix runtime PM imbalance on error

On 22/05/2020 14:41, Dinghao Liu wrote:
> The caller expects panfrost_job_hw_submit() to increase
> runtime PM usage counter. The refcount decrement on the
> error branch of WARN_ON() will break the counter balance
> and needs to be removed.
> 
> Signed-off-by: Dinghao Liu <dinghao.liu@....edu.cn>

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

Thanks,

Steve

> ---
> 
> Changelog:
> 
> v2: - Remove refcount decrement on the error path of
>        WARN_ON() rather than add refcount decrement
>        on the error path of pm_runtime_get_sync().
> ---
>   drivers/gpu/drm/panfrost/panfrost_job.c | 1 -
>   1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
> index 7914b1570841..1092d9754f0f 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_job.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_job.c
> @@ -150,7 +150,6 @@ static void panfrost_job_hw_submit(struct panfrost_job *job, int js)
>   		return;
>   
>   	if (WARN_ON(job_read(pfdev, JS_COMMAND_NEXT(js)))) {
> -		pm_runtime_put_sync_autosuspend(pfdev->dev);
>   		return;
>   	}
>   
>