Re: [PATCH v1 1/4] drm/msm/mdp5: stop overriding drvdata

[Abhinav Kumar <quic_abhinavk@quicinc.com>]

On 8/24/2022 1:29 AM, Dmitry Baryshkov wrote:
> On Wed, 24 Aug 2022 at 04:25, Abhinav Kumar <quic_abhinavk@quicinc.com> wrote:
>>
>>
>>
>> On 6/20/2022 2:30 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@linaro.org>
>>
>> Is this just for consistency across mdp5/dpu drivers?
>>
>> What issue was seen if mdp5's platform data is overwritten?
> 
> I think there was a crash in mdp5_destroy, but I did not capture the
> log at the moment.
> 
> As you can see, the mdp5_destroy() expects to get mdp5_kms pointer
> from the drvdata. However the msm_drv_probe sets the drvdata to
> msm_drm_private instance. Boom.

Yes, I see that msm_drv_probe sets the drvdata to msm_drm_private.
But I also see that mdp5_init then sets it to

platform_set_drvdata(pdev, mdp5_kms);

Does this not override it then?

Also seems like the commit which introduced it is present since april, 
this should have happened even earlier then right?

> 
>>
>>> ---
>>>    drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c | 19 +++++++++----------
>>>    1 file changed, 9 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
>>> index c668a4b27cc6..daf5b5ca7233 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
>>> @@ -651,9 +651,8 @@ 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)
>>> @@ -667,7 +666,7 @@ 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);
>>> @@ -816,8 +815,6 @@ 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;
>>> @@ -915,7 +912,7 @@ static int mdp5_init(struct platform_device *pdev, struct drm_device *dev)
>>>        return 0;
>>>    fail:
>>>        if (mdp5_kms)
>>> -             mdp5_destroy(pdev);
>>> +             mdp5_destroy(mdp5_kms);
>>>        return ret;
>>>    }
>>>
>>> @@ -975,7 +972,8 @@ 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("");
>>>
>>> @@ -985,7 +983,8 @@ 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("");
>>>
> 
> 
>