On Wed, Jan 16, 2013 at 6:36 AM, Daniel Vetter <daniel@xxxxxxxx> wrote: > On Wed, Jan 16, 2013 at 11:01 AM, Thierry Reding > <thierry.reding@xxxxxxxxxxxxxxxxx> wrote: >> drm_events_release() should be enough to clean up the events, but I >> suspect the reason why Laurent put that code in was that the drm_crtc >> private data still has a reference to the event and needs to clear it. >> Otherwise the next page flip won't be scheduled because .page_flip() >> would return -EBUSY. > > Hm, indeed we seem to have a nice bug in most drivers there :( > >> However, it seems like {tegra_dc,shmob_drm_crtc}_cancel_page_flip() >> could both be simplified a lot and just set their event to NULL. Then >> again, maybe keeping a separate reference isn't all that useful. Maybe >> the better thing to do here is iterate over the list of pending VBLANK >> events in *_finish_page_flip() and process each of them? That would >> allow more than one user-space process to queue page flips. > > I think we need a slightly more generally useful solution, since most > drivers are currently broken. I've read a bit through the code, but > short of refcounting drm events and adding event->file_priv checks at > relevent places I don't see a sane solution ... And even that one is > rather invasive. Do you have an idea? Imo doing the cleanup in each > driver will be rather error-prone, and since usually kms clients wait > for flips to complete, also guaranteed to be little tested. I suppose we could move the *pending_vblank_event to 'struct drm_crtc'.. I think probably all/most drivers need the same thing anyway. If a driver needs to do something special, it could just never set crtc->pending_vblank_event and instead do it's own cleanup. BR, -R > -Daniel > -- > Daniel Vetter > Software Engineer, Intel Corporation > +41 (0) 79 365 57 48 - http://blog.ffwll.ch > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > http://lists.freedesktop.org/mailman/listinfo/dri-devel -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html