RFC: page-flip with damage?
thellstrom at vmware.com
Sun Sep 24 17:41:45 UTC 2017
Page flips, while efficient on real hardware, aren't that efficient in
other situations, like for virtual devices with local, or even worse,
We might ending up forwarding or encoding a couple of full frames worth
of data instead of a small region at a cursor blink.
Now there is this extension EGL_KHR_swap_buffers_with_damage, and
gnome-shell/wayland on KMS also has a damage region that it forwards all
the way down to the function where page-flip is called.
So I'd like to start looking at page-flips with damage, meaning that the
damage is an optional hint to the device about what part of the contents
is actually updated. What would be the best way to implement this? I
figure this can be done within the atomic context with a region attached
to the plane state? Would we want to follow the EGL extension and
forward an array of rects or for simplicity use a single bounding box?
Both these options would be a great win.
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