On Thu, 7 Jul 2011 12:48:09 +0100 Chris Wilson <[email protected]> wrote:
> Page-flipping updates the scanout address, nukes the FBC compressed > image and so forces an FBC update so that the displayed image remains > consistent. However, page-flipping does not update the FBC registers > themselves, which remain pointing to both the old address and the old > CPU fence. Future updates to the new front-buffer (scanout) are then > undetected! > > This first approach to demonstrate the issue and highlight the fix, > simply disables FBC upon page-flip (a recompression will be forced on > every flip so FBC becomes immaterial) and then re-enables FBC in the > page-flip finish work function, so that the FBC registers are now > pointing to the new framebuffer and front-buffer rendering works once > more. > > Ideally, we want to only re-enable FBC after page-flipping is complete, > as otherwise we are just wasting cycles (along with an undesirable > wait-for-vblank which will halve the frame-rate of vsync'ed games) and > power (with needless recompression) whilst the page-flipping application > is still running. > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=33487 > Signed-off-by: Chris Wilson <[email protected]> > --- Yeah just disabling it is probably better than trying to let the hw figure out what to recompress since it likely won't be worthwhile. Reviewed-by: Jesse Barnes <[email protected]> -- Jesse Barnes, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
