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From: a.hajda@samsung•com (Andrzej Hajda)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2] imx-drm: imx-drm-core: add suspend/resume support
Date: Mon, 18 Aug 2014 15:11:54 +0200	[thread overview]
Message-ID: <53F1FB9A.4070305@samsung.com> (raw)
In-Reply-To: <53F1F866.1@samsung.com>

On 08/18/2014 02:58 PM, Andrzej Hajda wrote:
> On 08/18/2014 02:38 PM, Shawn Guo wrote:
>> Hi Andrzej,
>>
>> On Mon, Aug 18, 2014 at 09:43:19AM +0200, Andrzej Hajda wrote:
>>>> diff --git a/drivers/staging/imx-drm/imx-drm-core.c b/drivers/staging/imx-drm/imx-drm-core.c
>>>> index def8280d7ee6..ab41152089a3 100644
>>>> --- a/drivers/staging/imx-drm/imx-drm-core.c
>>>> +++ b/drivers/staging/imx-drm/imx-drm-core.c
>>>> @@ -696,6 +696,29 @@ static int imx_drm_platform_remove(struct platform_device *pdev)
>>>>  	return 0;
>>>>  }
>>>>  
>>>> +#ifdef CONFIG_PM_SLEEP
>>>> +static int imx_drm_suspend(struct device *dev)
>>>> +{
>>>> +	struct drm_device *drm_dev = dev_get_drvdata(dev);
>>>> +
>>>> +	drm_kms_helper_poll_disable(drm_dev);
>>> drm_dev can be NULL here. You should add check before.
>> The drvdata is set to drm_dev in drm_driver .load() hook.  So are you
>> saying that .suspend() hook could possibly be called before the .load()
>> hook gets called?
> .load hook is called after all components are attached to the master.
> So if suspend happen after probe of the master and before attaching the last
> component you will have NULL here, I guess.

Probably you can test it by disabling driver for one of drm components
and putting board in sleep mode.

Moreover I guess drvdata should be cleaned in .unload callback,
otherwise if for some reason one of components will be detached and suspend
happens drvdata will contain invalid pointer.

Regards
Andrzej

>
> Regards
> Andrzej
>
>> Shawn
>>
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>> +static int imx_drm_resume(struct device *dev)
>>>> +{
>>>> +	struct drm_device *drm_dev = dev_get_drvdata(dev);
>>>> +
>>>> +	drm_helper_resume_force_mode(drm_dev);
>>> ditto

  reply	other threads:[~2014-08-18 13:11 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-25  6:20 [PATCH v2] imx-drm: imx-drm-core: add suspend/resume support Shawn Guo
2014-08-18  6:25 ` Shawn Guo
2014-08-19  8:08   ` Russell King - ARM Linux
2014-08-19  9:16     ` Greg KH
2014-08-19  9:42       ` Russell King - ARM Linux
2014-08-18  7:43 ` Andrzej Hajda
2014-08-18 12:38   ` Shawn Guo
2014-08-18 12:58     ` Andrzej Hajda
2014-08-18 13:11       ` Andrzej Hajda [this message]
2014-08-19  7:21         ` Shawn Guo

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