On 31.10.2015 06:55, Daniel Vetter wrote: > Apparently pre-nv50 pageflip events happen before the actual vblank > period. Therefore that functionality got semi-disabled in > > commit af4870e406126b7ac0ae7c7ce5751f25ebe60f28 > Author: Mario Kleiner <mario.kleiner.de@xxxxxxxxx> > Date: Tue May 13 00:42:08 2014 +0200 > > drm/nouveau/kms/nv04-nv40: fix pageflip events via special case. > > Unfortunately that hack got uprooted in > > commit cc1ef118fc099295ae6aabbacc8af94d8d8885eb > Author: Thierry Reding <treding@xxxxxxxxxx> > Date: Wed Aug 12 17:00:31 2015 +0200 > > drm/irq: Make pipe unsigned and name consistent > > Trigering a warning when trying to sample the vblank timestamp for a > non-existing pipe. There's a few ways to fix this: > > - Open-code the old behaviour, which just enshrines this slight > breakage of the userspace ABI. > > - Revert Mario's commit and again inflict broken timestamps, again not > pretty. > > - Fix this for real by delaying the pageflip TS until the next vblank > interrupt, thereby making it accurate. > > This patch implements the third option. Since having a page flip > interrupt that happens when the pageflip gets armed and not when it > completes in the next vblank seems to be fairly common (older i915 hw > works very similarly) create a new helper to arm vblank events for > such drivers. What happens when the page flip interrupt arrives during a vertical blank period? Presumably the userspace event will be deferred until the next vertical blank period, but the flip might already take effect in the current one. > +/** > + * drm_arm_vblank_event - arm vblanke event after pageflip > + * @crtc: the source CRTC of the vblank event Ye olde vblanke event? ;) (typo, same in the previous comment) The function name in this comment doesn't match the name of the function it describes. -- Earthling Michel Dänzer | http://www.amd.com Libre software enthusiast | Mesa and X developer _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
