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

[Dmitry Baryshkov]

On 24/08/2022 20:20, Abhinav Kumar wrote:
> 
> 
> On 8/24/2022 1:29 AM, Dmitry Baryshkov wrote:
>> On Wed, 24 Aug 2022 at 04:25, Abhinav Kumar 
>> <quic_abhinavk at 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 at 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?

It does. But then the mdp5_pm_ops use msm_pm_prepare()/_complete(). And 
these calls expect the msm_drm_private instance in the drvdata. Maybe I 
stumbled upon this. I don't remember exactly, unfortunately.

> 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("");
>>>>
>>
>>
>>

-- 
With best wishes
Dmitry