Am 01.06.21 um 11:02 schrieb Michel Dänzer:
On 2021-05-27 11:51 p.m., Marek Olšák wrote:
3) Compositors (and other privileged processes, and display flipping) can't
trust imported/exported fences. They need a timeout recovery mechanism from the
beginning, and the following are some possible solutions to timeouts:
a) use a CPU wait with a small absolute timeout, and display the previous
content on timeout
b) use a GPU wait with a small absolute timeout, and conditional rendering will
choose between the latest content (if signalled) and previous content (if timed
out)
The result would be that the desktop can run close to 60 fps even if an app
runs at 1 fps.
FWIW, this is working with
https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1880 , even with
implicit sync (on current Intel GPUs; amdgpu/radeonsi would need to provide the
same dma-buf poll semantics as other drivers and high priority GFX contexts via
EGL_IMG_context_priority which can preempt lower priority ones).
Yeah, that is really nice to have.
One question is if you wait on the CPU or the GPU for the new surface to
become available? The former is a bit bad for latency and power management.
Another question is if that is sufficient as security for the display
server or if we need further handling down the road? I mean essentially
we are moving the reliability problem into the display server.
Regards,
Christian.
