linux-kernel - Re: [RFC] drm/msm/adreno: Balance pm

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Date:   Fri, 10 Feb 2023 08:10:00 -0800
From:   Rob Clark <robdclark@...il.com>
To:     Bjorn Andersson <quic_bjorande@...cinc.com>
Cc:     Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Akhil P Oommen <quic_akhilpo@...cinc.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC] drm/msm/adreno: Balance pm_runtime enable

On Fri, Feb 3, 2023 at 10:12 AM Bjorn Andersson
<quic_bjorande@...cinc.com> wrote:
>
> When any of the components in the mdss hierarchy fails to bind,
> previously bound components are being unbound again.
>
> One such case happens when the DP controller fails to find its bridge or
> panel, where adreno_unbind() will be invoked without adreno_load_gpu()
> being called to invoke pm_runtime_enable().
>
> The result is that once everything is bound the pm_runtime_get_sync()
> call find the power-domain to have a positive disable_depth, fails
> with -EACCESS and prevents the GPU device to be powered up.
>
> Move the pm_runtime_enable() to adreno_bind(), in order to balance it
> with any calls to adreno_unbind().

I think instead we want to move where the pm_runtime_disable() is..
since pm_runtime_enable() was moved because we can't actually enable
runpm until we have GMU firmware

BR,
-R

> Fixes: 4b18299b3365 ("drm/msm/adreno: Defer enabling runpm until hw_init()")
> Signed-off-by: Bjorn Andersson <quic_bjorande@...cinc.com>
> ---
>  drivers/gpu/drm/msm/adreno/adreno_device.c | 11 ++---------
>  1 file changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_device.c b/drivers/gpu/drm/msm/adreno/adreno_device.c
> index 36f062c7582f..ca38b837dedb 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_device.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_device.c
> @@ -432,15 +432,6 @@ struct msm_gpu *adreno_load_gpu(struct drm_device *dev)
>         if (ret)
>                 return NULL;
>
> -       /*
> -        * Now that we have firmware loaded, and are ready to begin
> -        * booting the gpu, go ahead and enable runpm:
> -        */
> -       pm_runtime_enable(&pdev->dev);
> -
> -       /* Make sure pm runtime is active and reset any previous errors */
> -       pm_runtime_set_active(&pdev->dev);
> -
>         ret = pm_runtime_get_sync(&pdev->dev);
>         if (ret < 0) {
>                 pm_runtime_put_sync(&pdev->dev);
> @@ -548,6 +539,8 @@ static int adreno_bind(struct device *dev, struct device *master, void *data)
>                 return PTR_ERR(gpu);
>         }
>
> +       pm_runtime_enable(dev);
> +
>         return 0;
>  }
>
> --
> 2.25.1
>