Re: [PATCH v2] drm/msm/mdp5: stop overriding drvdata

[Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>]

On 22/10/2022 00:58, Abhinav Kumar wrote:
> Hi Dmitry
>
> A couple of comments below.
>
> On 10/21/2022 12:26 PM, Dmitry Baryshkov wrote:
> > The rest of the code expects that master's device drvdata is the
> > struct msm_drm_private instance. Do not override the mdp5's drvdata.
> >
> > Fixes: 6874f48bb8b0 ("drm/msm: make mdp5/dpu devices master components")
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> > Reviewed-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
> > ---
> > Abhinav, Rob, please pick this for -fixes.
> >
> > This is an updated version of [1]. Fixed the read_mdp_hw_revision()
> > function. PM runtime isn't available at the moment, as priv->kms is not
> > set.
>
> Can you split them into two changes?

I can, but this would look a bit artificial.

Before the patch [1] there is no need to fix read_hw_revision, as 
pm_runtime_resume works correctly. And after [1] read_hw_revision can 
fail because pm_runtime_resume() wouldn't work before priv->kms being set

> Any reason fixing the read_mdp_hw_revision() needs to be in this?
> > [1] https://patchwork.freedesktop.org/patch/490326/?series=105392&rev=1
> >
> > ---
> >   drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c | 37 ++++++++++++++----------
> >   1 file changed, 22 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c 
> > b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> > index b0d21838a134..506c64940972 100644
> > --- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> > +++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
> > @@ -203,7 +203,7 @@ static int mdp5_set_split_display(struct msm_kms 
> > *kms,
> >                                 slave_encoder);
> >   }
> > -static void mdp5_destroy(struct platform_device *pdev);
> > +static void mdp5_destroy(struct mdp5_kms *mdp5_kms);
> >   static void mdp5_kms_destroy(struct msm_kms *kms)
> >   {
> > @@ -223,7 +223,7 @@ static void mdp5_kms_destroy(struct msm_kms *kms)
> >       }
> >       mdp_kms_destroy(&mdp5_kms->base);
> > -    mdp5_destroy(mdp5_kms->pdev);
> > +    mdp5_destroy(mdp5_kms);
> >   }
> >   #ifdef CONFIG_DEBUG_FS
> > @@ -519,9 +519,15 @@ static void read_mdp_hw_revision(struct mdp5_kms 
> > *mdp5_kms,
> >       struct device *dev = &mdp5_kms->pdev->dev;
> >       u32 version;
> > -    pm_runtime_get_sync(dev);
> > +    /* Manually enable the MDP5, as pm runtime isn't usable yet */
> > +    if (mdp5_enable(mdp5_kms)) {
>
> mdp5_enable() always seems to return 0 so do we need this if block?

No.

> > +        *major = 0;
> > +        *minor = 0;
> > +        return;
> > +    }
> > +
> >       version = mdp5_read(mdp5_kms, REG_MDP5_HW_VERSION);
> > -    pm_runtime_put_sync(dev);
> > +    mdp5_disable(mdp5_kms);
> >       *major = FIELD(version, MDP5_HW_VERSION_MAJOR);
> >       *minor = FIELD(version, MDP5_HW_VERSION_MINOR);
> > @@ -559,6 +565,8 @@ static int mdp5_kms_init(struct drm_device *dev)
> >       int irq, i, ret;
> >       ret = mdp5_init(to_platform_device(dev->dev), dev);
> > +    if (ret)
> > +        return ret;
> >       /* priv->kms would have been populated by the MDP5 driver */
> >       kms = priv->kms;
> > @@ -632,9 +640,8 @@ static int mdp5_kms_init(struct drm_device *dev)
> >       return ret;
> >   }
> > -static void mdp5_destroy(struct platform_device *pdev)
> > +static void mdp5_destroy(struct mdp5_kms *mdp5_kms)
> >   {
> > -    struct mdp5_kms *mdp5_kms = platform_get_drvdata(pdev);
> >       int i;
> >       if (mdp5_kms->ctlm)
> > @@ -648,7 +655,7 @@ static void mdp5_destroy(struct platform_device 
> > *pdev)
> >           kfree(mdp5_kms->intfs[i]);
> >       if (mdp5_kms->rpm_enabled)
> > -        pm_runtime_disable(&pdev->dev);
> > +        pm_runtime_disable(&mdp5_kms->pdev->dev);
> >       drm_atomic_private_obj_fini(&mdp5_kms->glob_state);
> >       drm_modeset_lock_fini(&mdp5_kms->glob_state_lock);
> > @@ -797,8 +804,6 @@ static int mdp5_init(struct platform_device *pdev, 
> > struct drm_device *dev)
> >           goto fail;
> >       }
> > -    platform_set_drvdata(pdev, mdp5_kms);
> > -
> >       spin_lock_init(&mdp5_kms->resource_lock);
> >       mdp5_kms->dev = dev;
> > @@ -839,9 +844,6 @@ static int mdp5_init(struct platform_device *pdev, 
> > struct drm_device *dev)
> >        */
> >       clk_set_rate(mdp5_kms->core_clk, 200000000);
> > -    pm_runtime_enable(&pdev->dev);
> > -    mdp5_kms->rpm_enabled = true;
> > -
> >       read_mdp_hw_revision(mdp5_kms, &major, &minor);
> >       mdp5_kms->cfg = mdp5_cfg_init(mdp5_kms, major, minor);
> > @@ -893,10 +895,13 @@ static int mdp5_init(struct platform_device 
> > *pdev, struct drm_device *dev)
> >       /* set uninit-ed kms */
> >       priv->kms = &mdp5_kms->base.base;
> > +    pm_runtime_enable(&pdev->dev);
> > +    mdp5_kms->rpm_enabled = true;
> > +
> >       return 0;
> >   fail:
> >       if (mdp5_kms)
> > -        mdp5_destroy(pdev);
> > +        mdp5_destroy(mdp5_kms);
> >       return ret;
> >   }
> > @@ -953,7 +958,8 @@ static int mdp5_dev_remove(struct platform_device 
> > *pdev)
> >   static __maybe_unused int mdp5_runtime_suspend(struct device *dev)
> >   {
> >       struct platform_device *pdev = to_platform_device(dev);
> > -    struct mdp5_kms *mdp5_kms = platform_get_drvdata(pdev);
> > +    struct msm_drm_private *priv = platform_get_drvdata(pdev);
> > +    struct mdp5_kms *mdp5_kms = to_mdp5_kms(to_mdp_kms(priv->kms));
> >       DBG("");
> > @@ -963,7 +969,8 @@ static __maybe_unused int 
> > mdp5_runtime_suspend(struct device *dev)
> >   static __maybe_unused int mdp5_runtime_resume(struct device *dev)
> >   {
> >       struct platform_device *pdev = to_platform_device(dev);
> > -    struct mdp5_kms *mdp5_kms = platform_get_drvdata(pdev);
> > +    struct msm_drm_private *priv = platform_get_drvdata(pdev);
> > +    struct mdp5_kms *mdp5_kms = to_mdp5_kms(to_mdp_kms(priv->kms));
> >       DBG("");

--
With best wishes
Dmitry