On Tue, Sep 20, 2022 at 03:56:18PM +0200, Thomas Zimmermann wrote: > Set partial updates on a plane if the framebuffer has not been changed > on an atomic commit. If such a plane has damage clips, the driver will > use them; otherwise the update is effectively empty. Planes that change > their framebuffer still perform a full update. I have a feeling you're sort of papering over some inefficient userspace that's asking updates on planes that don't actually need them. I'm not sure adding more code for that is a particularly great idea. Wouldn't it be better to just fix the userspace code? Any property change on the plane could need a full plane update as well (eg. some color mangement stuff etc.). So you'd have to keep adding exceptions to that list whenever new properties are added. And I think the semantics of the ioctl(s) has so far been that basically any page flip (whether or not it actually changes the fb) still ends up doing whatever flushing is needed to guarantee the fb contents are up to date on the screen (if someone sneaked in some front buffer rendering in between). Ie. you could even use basically a nop page flip in place of dirtyfb. Another thing the ioctls have always done is actually perform the commit whether anything changed or nor. That is, they still do all the same the same vblanky stuff and the commit takes the same amount of time. Not sure if your idea is to potentially short circuit the entire thing and make it take no time at all? -- Ville Syrjälä Intel
