[PATCH 2/3] drm/gma500: Fix crtc_vblank reference leak when userspace queues multiple events

[Hans de Goede]

Hi Michel,

On 9/6/22 12:25, Michel Dänzer wrote:
> On 2022-09-05 15:37, Hans de Goede wrote:
>> The gma500 page-flip code kinda assume that userspace never queues more
>> then 1 vblank event. So basically it assume that userspace does:
>>
>> - page-flip
>> - wait for vblank event
>> - render
>> - page-flip
>> - etc.
>>
>> In the case where userspace would submit 2 page-flips without waiting
>> for the first to finish, the current code will just overwrite
>> gma_crtc->page_flip_event with the event from the 2nd page-flip.
> 
> This cannot happen. Common code returns -EBUSY for an attempt to submit a page flip while another one is still pending.

Ah I did not know that, that is very useful to know, thank you.

I will drop this patch for the next version of this patch-set
(which will include some further fixes).

Regards,

Hans