linux-kernel - Re: [PATCH v3 2/8] drm/msm: Take single rpm refcount on behalf of all submits

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Message-ID: <CAF6AEGs7zKDoRY=ijxFQvaZig=UiSPgWkJFA-PY2MTxKWr5bpw@mail.gmail.com>
Date:   Sun, 31 Jul 2022 08:56:01 -0700
From:   Rob Clark <robdclark@...il.com>
To:     Akhil P Oommen <quic_akhilpo@...cinc.com>
Cc:     freedreno <freedreno@...ts.freedesktop.org>,
        dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Jordan Crouse <jordan@...micpenguin.net>,
        Jonathan Marek <jonathan@...ek.ca>,
        Douglas Anderson <dianders@...omium.org>,
        Matthias Kaehlcke <mka@...omium.org>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Sean Paul <sean@...rly.run>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/8] drm/msm: Take single rpm refcount on behalf of all submits

On Sat, Jul 30, 2022 at 2:41 AM Akhil P Oommen <quic_akhilpo@...cinc.com> wrote:
>
> Instead of separate refcount for each submit, take single rpm refcount
> on behalf of all the submits. This makes it easier to drop the rpm
> refcount during recovery in an upcoming patch.
>
> Signed-off-by: Akhil P Oommen <quic_akhilpo@...cinc.com>
> ---
>
> (no changes since v1)

I see no earlier version of this patch?

>
>  drivers/gpu/drm/msm/msm_gpu.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/msm_gpu.c b/drivers/gpu/drm/msm/msm_gpu.c
> index c8cd9bf..e1dd3cc 100644
> --- a/drivers/gpu/drm/msm/msm_gpu.c
> +++ b/drivers/gpu/drm/msm/msm_gpu.c
> @@ -663,11 +663,12 @@ static void retire_submit(struct msm_gpu *gpu, struct msm_ringbuffer *ring,
>         mutex_lock(&gpu->active_lock);
>         gpu->active_submits--;
>         WARN_ON(gpu->active_submits < 0);
> -       if (!gpu->active_submits)
> +       if (!gpu->active_submits) {
>                 msm_devfreq_idle(gpu);
> -       mutex_unlock(&gpu->active_lock);
> +               pm_runtime_put_autosuspend(&gpu->pdev->dev);
> +       }
>
> -       pm_runtime_put_autosuspend(&gpu->pdev->dev);
> +       mutex_unlock(&gpu->active_lock);
>
>         msm_gem_submit_put(submit);
>  }
> @@ -756,14 +757,17 @@ void msm_gpu_submit(struct msm_gpu *gpu, struct msm_gem_submit *submit)
>
>         /* Update devfreq on transition from idle->active: */
>         mutex_lock(&gpu->active_lock);
> -       if (!gpu->active_submits)
> +       if (!gpu->active_submits) {
> +               pm_runtime_get(&gpu->pdev->dev);
>                 msm_devfreq_active(gpu);
> +       }
>         gpu->active_submits++;
>         mutex_unlock(&gpu->active_lock);
>
>         gpu->funcs->submit(gpu, submit);
>         gpu->cur_ctx_seqno = submit->queue->ctx->seqno;
>
> +       pm_runtime_put(&gpu->pdev->dev);

this looks unbalanced?

BR,
-R

>         hangcheck_timer_reset(gpu);
>  }
>
> --
> 2.7.4
>