On Thu, Oct 11, 2012 at 5:53 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote: > On Thu, 11 Oct 2012 14:30:29 +1000, Dave Airlie <airlied at gmail.com> wrote: >> From: Dave Airlie <airlied at redhat.com> >> >> While playing with MPX and sw cursor I noticed page flips won't >> end up misrendering some bits, so the sw cursor was replacing the >> bits on the wrong pixmap. >> >> Fix the damage handling to be correct and append damage before swapping >> the pointers and process damage after. >> >> This fixes misrendering with MPX cursors under a fullscreen compositor, >> that pageflips. > > Wow, what magic is this? The created region is the same and > front->drawable left unmodified by the exchange. The exchange only > manipulates the devPrivates and has not other side effects. The only > uncertain quantity there is the intel_glamor_exchange_buffers()... > > So the change is that we append the same damage to the same drawable > earlier, yet still process that damage at the same time, with no > apparent side-effects between the two operations. I'm just not > understanding why this has any effect. Hence why I didn't do it right in the first place, I thought I understood how damage worked :-) We have pre-rendering damage reporting and post-rendering damage reporting!, so sw cursors really wants it before the fact so it can copy the area out underneath itself, damage append will process the pre-damage stuff, and pending will process post-damage hooks. Dave.
