Hi Michel & pekka >>Yes, drm_handle_vblank must be called before drm_crtc_send_vblank_event, >>otherwise it's not surprising that the timestamp in the event is wrong. :) Yes. our code call drm_crtc_send_vblank event first. The orignal fps is 60, but if I swap the order of drm_crtc_send_vblank_event and drm_handle_vblank, the fps drop to 30fps.
@pekka >>Weston schedules a repaint based on the pageflip timestamp. If the >>timestamp is in the past by a whole refresh period, the computed new >>deadline will be in the past as well, so Weston will attempt to repaint >>as soon as possible. I agree with this. >>The intended behaviour is that Weston repaints at most once for each >>display refresh cycle, the deadline being 7 ms (if using the default >>value of repaint-window) before the next vblank. In other words, there >>should be a significant delay (say, 50-90% of a refresh period) between >>receiving the pageflip event and repaint. I can't understand this. I use weston 1.9 now, the repaint_msc is 7ms. our code always execute output_repaint_timer_handler() as soon as possible because msec always lower than 1ms. Why there is delay? Best Regards Nancy 2018-05-31 0:12 GMT+08:00 Michel Dänzer <[email protected]>: > On 2018-05-30 02:48 PM, Pekka Paalanen wrote: > > On Wed, 30 May 2018 18:33:40 +0800 > > zou lan <[email protected]> wrote: > > > >> Hi pekka > >> > >> I'm not familiar with kernel. I know part of drm driver is implement by > >> ourself. I check the vblank callback function, it sends pageflip event > >> first if there is a frame complete, update vblank timestamp later. > >> > >> I don't know why the owner write code like this. but if I swap the code > >> order, the fps decrease a lot. > > > > Hi Nancy, > > > > I do not know your hardware, so I cannot say why fps decreases, but the > > order of sending event first and updating the timestamp later does > > sound wrong to me. > > Yes, drm_handle_vblank must be called before drm_crtc_send_vblank_event, > otherwise it's not surprising that the timestamp in the event is wrong. :) > > > -- > Earthling Michel Dänzer | http://www.amd.com > Libre software enthusiast | Mesa and X developer > >
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