https://bugs.freedesktop.org/show_bug.cgi?id=38800 --- Comment #28 from Alex Deucher <agd5f@xxxxxxxxx> 2011-07-06 20:07:58 PDT --- (In reply to comment #27) > (In reply to comment #22) > > FWIW, the pageflip interrupts weren't too reliable at least on 6xx, but they > > seemed to work ok on 7xx+. > > Thanks for the info Alex. Can you define "work ok"? Is this "no apparent > problems, but only lightly tested" or more like "works nine out of ten times"? > No apparent problems, but only lightly tested. > > Also, I can see problems where you might not get > > interrupts for some flips if a later base update write comes in via the CP > > before the irq handler has acked the interrupt from the frame before it. > > When would this happen? During or close to a mode-set? Not during normal page > flipping, no? I thought that so far all crtc updates go directly via mmio > instead of the CP? Or does Atombios use the CP? > All current pageflipping and modesetting happens via MMIO. I'm not even sure it's a problem, just thinking out loud. > >FWIW, I asked internally and the closed driver uses vblanks. > > Ok, that's a bit scary. Do you know if it is because it is supposed to be "good > enough" or due to some real problems? I do know that the Catalyst drivers were > far from perfect wrt. vsync'ed swapping in the past. My own toolkit implements > a couple of crazy workarounds for some oddities i saw at least on Windows and > OS/X, can't remember if it was on Linux as well. So from my experience i'm not > sure if i personally would count that as a pro or contra argument against using > something else than vblank irq's ;-) I think it was mostly due to using the same well tested code across generations since pre-r6xx asics didn't have the flip interrupts. Things might have changed since I last asked months ago. I can check again. I'm assuming the flip interrupts were added for a reason... > > At least evergreen seems to also have vline interrupts? One could (ab)use them > as well to fake a home-grown pageflip completion interrupt, e.g., by triggering > one at scanline 1, immediately after end of vblank and then just checking in > the vline irq if the update_pending bit is clear -> pageflip completed. All asics support vline interrupts. -- Configure bugmail: https://bugs.freedesktop.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
