(In reply to Andrey Grodzovsky from comment #12)
> Can you load the kernel with grub command line amdgpu.vm_update_mode=3 to
> force CPU VM update mode and see if this helps ?

Sure. Too early yet to say "hurray", but at an uptime of one hour, currently,
4.17.2 survived with amdgpu.vm_update_mode=3 already about 20 times longer than
without that option before the first crash.

One (probably just informal) message is emitted by the kernel:
[   19.319565] CPU update of VM recommended only for large BAR system

Can you explain a little: What is a "large BAR system", and what does the
vm_update_mode=3 option actually cause? Should I expect any weird side effects
to look for?

BTW: Not a result of that option, but of the kernel version, seems to be the
fact that the shader clock keeps at a pretty high frequency all the time - even
without any 3d or compute load, just displaying a quiet 4k/60Hz desktop image:

cat pp_dpm_sclk
0: 214Mhz 
1: 481Mhz 
2: 760Mhz 
3: 1020Mhz 
4: 1102Mhz 
5: 1138Mhz 
6: 1180Mhz *
7: 1220Mhz 

Much lower shader clocks are used only if I lower the refresh rate of the
screen. Is there a reason why the shader clocks should stay high even in the
absence of 3d/compute load?

(I would have better understood if the minimum memory clock was depending on
the refresh rate, but memory clock stays as low as with the older kernels.)