Xserver opengl problems on i5-8259U

[Dmitry Dudkin]

I have installed 18.04.1 server on Intel NUC NUC8i5BEH with minimal xinit and xserver-xorg-video-intel. But it has 2 major issues:
1. Huge Xorg CPU usage with intel driver...more than 110% on glxgears without vsync (with modesetting driver Xorg has zero CPU usage and very good Opengl performance)
2. on DRI3 glxgears it skip most frames and display one frame every 60-70 frames but reported FPS is doubled than on DRI2

to reproduce a problem install fresh server image of 18.04 and then install minimal xinit+xserver-xorg-video-intel. Put 20-intel.conf to enable intel driver. Run X by startx and then run glxgears.

20-intel.conf:

Section "Device"
   Identifier "Intel Graphics"
   Driver "intel"
   Option "TearFree" "true"
# Option "DRI" "3"
EndSection

P.S. Before 18.04 I tried 16.04 with HWE kernel...on stock Xserver and Intel driver it just crash. On latest HWE xserver and HWE Intel driver it works the same as 18.04 because it has the same versions. But with old 1.18 xserver and HWE intel driver it works in DRI2 mode...Xorg CPU usage just 10% instead of 110% on xserver 1.19...The only problem - poor OPENGL performance (glxgears 5400 fps vs 8000 fps on 1.19 xserver)

[Cristian Aravena Romero (caravena)]

Please create a new report with this command in the terminal:

$ ubuntu-bug xserver-xorg-video-intel

Best regards,
--
Cristian Aravena Romero (caravena)