Hello. After upgrading my kernel to 4.14 I noticed strange behavior: If I load X (KDE 3.5.10 session with built-in compositor [kompmgr], self-compiled with many patches, X server 1.19.5, nouveau DDX git) and start to use seamonkey 2.49 (again, self-compiled with gtk2 toolkit, not default gtk3) - after some hours of use X started to eat a lot of CPU time, new windows appear after delay, glxgears slow down to 11 fps or so from default 60. If I restart X session - everything back to normal, for few hours. If I quit seamonkey - CPU usage drops. But if I start it up again - CPU load returns quickly, and not go down until X restart.
Seamonkey use hw compositing (force-enabled) and multiprocess experimental option. Problem is, exactly same seamonkey with same set of tabs work fine on 4.12.0 kernel!
I set architecture to ia32, even if kernel compiled for x86_64 , because all my userspace is 32-bit.
01:00.0 0300: 10de:0606 (rev a2) (prog-if 00 [VGA controller])
01:00.0 VGA compatible controller: NVIDIA Corporation G92 [GeForce 8800 GS] (rev a2) (prog-if 00 [VGA controller])
X log, dmesg, opreport data will follow.
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It seems setting option DRI to "2" instead of "3" workarounds this problem.
Bug still here on 4.14.9-x64.
But it seems if I use "xset dpms force standby" X also doesn't eat CPU anymore. If X enters such state by default after some time of user inactivity - it also don't eat CPU time. Unfortunately, I can't do anything useful wih seamonkey if my screen is off.
This bug still around for me with 4.15.0