Comment 141 for bug 1803179

Back with some more info -- although I start to feel that this is getting a bit futile. Hibernation appears to be working again if GuC loading is disabled in i915, so that was probably a separate issue for me. Currently, it seems the machine is fairly stable when running applications with DRI_PRIME=1 or plugging in an external monitor, and power cycling the card with `DRI_PRIME=1 glxinfo` can put it back to state 1 after sleep or hibernation.

However, resuming after sleep with an external display connected (i.e., the card is powered on before and after suspend) leads to a non-responsive X server and display manager. I can still switch to another terminal and observe DRI notifier timeout errors from nouveau in dmesg if that rings a bell for someone. Restarting X fixes the problem somewhat, but connecting a display after that freezes the computer for good, during which the monitor complains about unsupported input. At any rate, plugging out the external display to let the card power down before sleep looks like a workaround (this is, of course, after applying the kernel patches in this thread).