Created attachment 129731 [details]
Xorg.0.log, no problem occurring, smooth video
Xorg version: 1.19.1 (archlinux's package)
xf86-video-intel version: git's latest: 860c3664 (built from source)
uname -rm: 4.9.8-1-ARCH x86_64
lspci | grep VGA: 00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller (rev 06)
Video playback looks like it's very low FPS, maybe ~10FPS or less. It doesn't look like a video acceleration problem, the CPU usage is still very small. It looks like a refresh problem.
An interesting thing is that the problem disappears as long as the mouse is moving, as if it forces a high refresh rate. It reappears as soon as the mouse is still.
The problem doesn't happen when I set
Option "DRI" "2"
in the config.
I also set Option "TearFree" "true" but I don't think it makes any difference, the problem also happens without TearFree (with DRI3).
I don't have compton or any other compositor.
Created attachment 129732 [details]
Xorg.0.log, problem occurring, low FPS video