Re: [PATCH 2/3] drm/gma500: Fix crtc_vblank reference leak when userspace queues multiple events
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
Re: [PATCH 2/3] drm/gma500: Fix crtc_vblank reference leak when userspace queues multiple events
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. -- Earthling Michel Dänzer| https://redhat.com Libre software enthusiast | Mesa and Xwayland developer
