Bug 114431

Created attachment 208711 [details]
Kernel Oops

For quite some time now I've been struggling to get stable hardware acceleration from my Core i5 6600K. I'm running Arch on an MSI Z170A GAMING M7 mainboard.
Whenever I try to use hardware acceleration on the IGD (chromium, glxgears) the display will just freeze. I can still log in remotely and the machine works fine otherwise. dmesg will contain an oops like the one attaached.

I had this working briefly with 4.4.3, but after the first hang downgrading wouldn't help either.
My current /proc/cmdline:

initrd=/initramfs-linux.img initrd=/intel-ucode.img rw <luks-setup> root=/dev/mapper/e1 rootflags=subvol=root,device=/dev/mapper/e1,device=/dev/mapper/e2,compress=lzo intel_iommu=on intel_iommu=igfx_off i915.preliminary_hw_support=1

The preliminary_hw_support is what made things work with 4.4.3.
My current i915 modprobe:
options i915 enable_rc6=1 enable_fbc=1 lvds_downclock=1 semaphores=1

As suggested by https://wiki.archlinux.org/index.php/Intel_graphics I tried booting with i915.enable_rc6=0 (also removing the option from the modprobe.conf) but without success. Also i915.enable_execlists=0 or switching to uxa acceleration didn't help. So far the only thing that reliably lets me use the machine is disabling DRI. But since that forces me to move the mouse for the screen to refresh at all that's not really an option. Watching movies while constantly jiggling the mouse is more than just tedious.
I can't find any related errors in the Xorg log.