On Mon, Aug 22, 2016 at 09:39:17PM -0300, Paulo Zanoni wrote: > 2016-08-18 5:21 GMT-03:00 Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>: > > Only fbc1 is tied to using a fence. Later iterations of fbc are more > > flexible and allow operation on unfenced frontbuffers. > > > > Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > > Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx> > > Cc: "Zanoni, Paulo R" <paulo.r.zanoni@xxxxxxxxx> > > Hi > > I see this patch was applied. Now, on my Skylake machine, if I boot > with i915.enable_fbc=1 I'll get FIFO underruns under fbcon. Just > booting already gives me a FIFO underrun message, and then if I "sudo > systemctl stop lightdm" I'll get a constantly-blinking screen. > > Of course, applying the patch that disables FBC after a FIFO underrun > will help stopping the ever-blinking fbcon, but I think we should try > to avoid the underruns in the places we know we can, and leave the > "disable FBC on FIFO underruns" just for the cases we're not expecting. > > Also, please remember that I mentioned there are FBC workarounds for > untiled that we still don't implement (although when I re-read my > email it may sound like I suggested the workarounds are for non-GTT > tracking). IMHO this argument alone should > have prevented this patch from being merged... > > Based on that, can we please revert this patch? I'm afraid some people > would consider these underruns as blockers to enabling FBC, so it's > probably better to enable FBC only on X tiled for now, and leave this > for when we know how to prevent the underrun (possibly by implementing > the missing WAs). Sure you can disable FBC - just note that typically framebuffers will be unfenced. -Chris -- Chris Wilson, Intel Open Source Technology Centre _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
