On 10/07/2014 05:56 AM, Mark yao wrote:
> On 2014?09?30? 21:31, Andrzej Hajda wrote:
>> Hi Mark,
> Hi Andrzej,
> Sorry for replying late, I have a vacation before.
> Thanks for your review.
>> On 09/30/2014 03:03 PM, Mark Yao wrote:
>>> From: Mark yao <mark.yao at rock-chips.com>
>>>
(...)
>>> +#ifdef CONFIG_PM_SLEEP
>>> +static int rockchip_drm_suspend(struct drm_device *dev, pm_message_t state)
>>> +{
>>> + struct drm_connector *connector;
>>> +
>>> + drm_modeset_lock_all(dev);
>>> + list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
>>> + int old_dpms = connector->dpms;
>>> +
>>> + if (connector->funcs->dpms)
>>> + connector->funcs->dpms(connector, DRM_MODE_DPMS_OFF);
>>> +
>>> + /* Set the old mode back to the connector for resume */
>>> + connector->dpms = old_dpms;
>>> + }
>>> + drm_modeset_unlock_all(dev);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int rockchip_drm_resume(struct drm_device *dev)
>>> +{
>>> + struct drm_connector *connector;
>>> +
>>> + drm_modeset_lock_all(dev);
>>> + list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
>>> + if (connector->funcs->dpms)
>>> + connector->funcs->dpms(connector, connector->dpms);
>>> + }
>>> + drm_modeset_unlock_all(dev);
>>> +
>>> + drm_helper_resume_force_mode(dev);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int rockchip_drm_sys_suspend(struct device *dev)
>>> +{
>>> + struct drm_device *drm_dev = dev_get_drvdata(dev);
>>> + pm_message_t message;
>>> +
>>> + if (pm_runtime_suspended(dev))
>>> + return 0;
>>> +
>>> + message.event = PM_EVENT_SUSPEND;
>>> +
>>> + return rockchip_drm_suspend(drm_dev, message);
>> drm_dev can be NULL here, it can happen when system is suspended
>> before all components are bound. It can also contain invalid pointer
>> if after successfull drm initialization de-initialization happens for
>> some reason.
>>
>> Some workaround is to check for null here and set drvdata to null on
>> master unbind. But I guess it should be protected somehow to avoid races
>> in accessing drvdata.
> So, can I use the way that check for null here and set drvdata to null
> on master unbind?
> I don't know which way is better to protect somehow.
It seems to be a core problem, I have proposed some solution using drm
driver PM callbacks [1]
but it appears these callbacks are obsolete, so different solution
should be found. According to
Russel probably some extension of component framework.
As a temporary solution I guess null checks should work in most cases.
Regards
Andrzej
[1]: https://lkml.org/lkml/2014/10/3/60
>
> -Mark.
>>> +}
>>> +
>>> +static int rockchip_drm_sys_resume(struct device *dev)
>>> +{
>>> + struct drm_device *drm_dev = dev_get_drvdata(dev);
>>> +
>>> + if (!pm_runtime_suspended(dev))
>>> + return 0;
>>> +
>>> + return rockchip_drm_resume(drm_dev);
>> Ditto.
>>
>> Regards
>> Andrzej
>>
>>
