Comment 54 for bug 1798961

The workaround from #42 seems to make the hard lockup less frequent for me, but it's not completely gone. I still experience a complete freeze from time to time. It's completely aleatory, and it doesn't seem related to the workload, although I suspect that it's related to powersaving. From my experience, the probability of being hit by the freeze increases around a standby or resume event, or around plugging / unplugging the laptop.

When the hardlock occurs, the only thing I can do is to turn off the laptop by long-pressing the power button. I can't switch to a virtual tty, I can't reach the machine via SSH, REISUB doesn't work, etc.

Upon restarting, there's absolutely nothing in the kernel logs that could be remotely related to the lockup. In fact, many times the last entry in `journalctl -b -1` is from several minutes *before* the lockup.

I suspected of a hardware problem for a while, but the fact that every hardware test I've run finds nothing, coupled with the fact that the frequency of the freeze has *definitely* decreased with successive Ubuntu/kernel/mesa versions convinced me otherwise.

My specs:
 - Lenovo ThinkPad T470s
 - Intel Core i5-7200U (Kaby Lake)
 - Intel HD Graphics 620 (rev 02)
 - Currenly on Ubuntu 18.10, kernel 4.18.0-17-generic, although for me this bug has been present ever since Ubuntu 17.10, kernel 4.13