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From:   Robert Foss <robert.foss@linaro.org>
Date:   Thu, 27 May 2021 13:57:12 +0200
Message-ID: <CAG3jFys93VO6WhqkntpNuFGCdKNedz3HLpJEJJa=jVPb+SU+uw@mail.gmail.com>
Subject: Re: [PATCH -next] drm/bridge: cdns: Fix PM reference leak in cdns_dsi_transfer()
To:     Zou Wei <zou_wei@huawei.com>
Cc:     Andrzej Hajda <a.hajda@samsung.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
        Jonas Karlman <jonas@kwiboo.se>,
        Jernej Skrabec <jernej.skrabec@gmail.com>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        linux-kernel <linux-kernel@vger.kernel.org>
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Reviewed & pushed to drm-misc-next.

On Mon, 24 May 2021 at 09:02, Zou Wei <zou_wei@huawei.com> wrote:
>
> pm_runtime_get_sync will increment pm usage counter even it failed.
> Forgetting to putting operation will result in reference leak here.
> Fix it by replacing it with pm_runtime_resume_and_get to keep usage
> counter balanced.
>
> Reported-by: Hulk Robot <hulkci@huawei.com>
> Signed-off-by: Zou Wei <zou_wei@huawei.com>
> ---
>  drivers/gpu/drm/bridge/cdns-dsi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/bridge/cdns-dsi.c b/drivers/gpu/drm/bridge/cdns-dsi.c
> index 76373e3..b31281f 100644
> --- a/drivers/gpu/drm/bridge/cdns-dsi.c
> +++ b/drivers/gpu/drm/bridge/cdns-dsi.c
> @@ -1028,7 +1028,7 @@ static ssize_t cdns_dsi_transfer(struct mipi_dsi_host *host,
>         struct mipi_dsi_packet packet;
>         int ret, i, tx_len, rx_len;
>
> -       ret = pm_runtime_get_sync(host->dev);
> +       ret = pm_runtime_resume_and_get(host->dev);
>         if (ret < 0)
>                 return ret;
>
> --
> 2.6.2
>