Comment 26 for bug 1727662

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penalvch (penalvch) wrote : Re: Crashes after unlock: [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

Alexander Kops, yes please. Also, it would be helpful to attach the information via SSH or netconsole via https://help.ubuntu.com/community/DebuggingSystemCrash .

In addition, to follow up:
1) Have the issues happened without having to lock the computer (i.e. during active daily use, with the PC in or not in the docking station)? No need for a test to this specifically, just as per your recollection?
2) When the computer is plugged into the docking station, does the OS recognize this by showing the battery icon in a charging/charged state?
3) Does this issue happen if you don't dock the computer in the docking station, and only have the power cord plugged into the computer directly (i.e. no external monitors plugged)?
4) Does the issue happen bypassing the docking station, and plugging the monitors and power directly into the laptop?
5) Does this issue happen if the PC has nothing connected (i.e. keep it on battery, and no external monitors)?
6) Regarding your question in https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1727662/comments/12 :
>"Can you advise on how to narrow down the error to the actual state where it happens?"

What seems strange is how after locking the computer with it plugged into the docking station, presuming the power cord is plugged into the docking station, there are a few events in order of most to least interest:
* The PC is set to suspend on battery. I originally presumed that this is the issue trigger, but was thrown off as the GUI screenshots are set to do this only on battery.
* The screen dims when inactive. You could try rapidly toggling the brightness max up/down.
* The WiFi turning off. You could try toggling the WiFi hard swich/key combo repeatedly.
* The lock event itself. You could try locking and immediately unlocking multiple times in quick succession.