[PATCH v3] drm/exynos: fix kernel panic issue at drm releasing

[Daniel Stone]

Hi Inki,

On 12 January 2016 at 06:25, Inki Dae <inki.dae at samsung.com> wrote:
> 2016년 01월 12일 04:00에 Daniel Stone 이(가) 쓴 글:
>> On 8 January 2016 at 08:46, Inki Dae <inki.dae at samsung.com> wrote:
>>> Changelog v3:
>>> - initialize only device specific things. Each page flip event object
>>>   is created by DRM core so DRM core should release the object including
>>>   incrementing event space.
>>
>> I'm a bit confused here; we no longer call event->base.destroy(),
>> because you say that the DRM core should release it. But how does the
>> DRM core know to release the event? From the core point of view, the
>> event disappears into the driver, and it is no longer tracked.
>
> DRM core would need something to track the events. I think basically, someone who created one object should also destroy the object.

You're right, but this doesn't exist until Daniel Vetter's rather
larger patchset which is still pending merge.

>> As Daniel says though, later versions handle all this in the core in a
>> much more clean way, so we can remove these from the drivers then.
>
> So I think it's not reasonable for specific driver to destroy the object created by core although there is a memory leak. However, the memory leak would be more critical than temporary codes.
> Ok, I will merge this patch with more comments which will say the object will be destroyed by core part later.

Also, by stealing the event out of crtc_state->event and moving it to
exynos_crtc->event, you can argue that we have quite explictly removed
the responsibility from the core. ;)

Thanks for handling this!

Cheers,
Daniel