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From:   Qiang Yu <yuq825@gmail.com>
Date:   Sat, 20 Apr 2019 16:40:30 +0800
Message-ID: <CAKGbVbtkE5K0CgyMjdOBoLRCzqQ-EDbbH67N9SbeWr1wTB_OHg@mail.gmail.com>
Subject: Re: [PATCH v2 6/6] drm/lima: handle shared irq case for lima_pp_bcast_irq_handler
To:     Peter Griffin <peter.griffin@linaro.org>
Cc:     linux-arm-kernel@lists.infradead.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        John Stultz <john.stultz@linaro.org>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>, robh+dt@kernel.org,
        mark.rutland@arm.com, p.zabel@pengutronix.de, xuwei5@hisilicon.com,
        Michael Turquette <mturquette@baylibre.com>, sboyd@kernel.org,
        dri-devel <dri-devel@lists.freedesktop.org>,
        devicetree@vger.kernel.org, linux-clk@vger.kernel.org,
        lima@lists.freedesktop.org, Rob Herring <robh@kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Pushed to drm-misc-next.

Thanks,
Qiang

On Fri, Apr 19, 2019 at 4:35 PM Peter Griffin <peter.griffin@linaro.org> wrote:
>
> On Hikey board all lima ip blocks are shared with one irq.
> This patch avoids a NULL ptr deref crash on this platform
> on startup. Tested with Weston and kmscube.
>
> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> Cc: Rob Herring <robh@kernel.org>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Qiang Yu <yuq825@gmail.com>
> ---
>  drivers/gpu/drm/lima/lima_pp.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/lima/lima_pp.c b/drivers/gpu/drm/lima/lima_pp.c
> index d29721e..8fef224 100644
> --- a/drivers/gpu/drm/lima/lima_pp.c
> +++ b/drivers/gpu/drm/lima/lima_pp.c
> @@ -64,7 +64,13 @@ static irqreturn_t lima_pp_bcast_irq_handler(int irq, void *data)
>         struct lima_ip *pp_bcast = data;
>         struct lima_device *dev = pp_bcast->dev;
>         struct lima_sched_pipe *pipe = dev->pipe + lima_pipe_pp;
> -       struct drm_lima_m450_pp_frame *frame = pipe->current_task->frame;
> +       struct drm_lima_m450_pp_frame *frame;
> +
> +       /* for shared irq case */
> +       if (!pipe->current_task)
> +               return IRQ_NONE;
> +
> +       frame = pipe->current_task->frame;
>
>         for (i = 0; i < frame->num_pp; i++) {
>                 struct lima_ip *ip = pipe->processor[i];
> --
> 2.7.4
>