Bug #2932

panic if laptop sleeps with external monitor plugged in

Added by cmusser about 5 years ago. Updated about 4 years ago.

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If my laptop goes to sleep with a monitor plugged into the DisplayPort, it cannot wake successfully. When I wake it (with mouse or keyboard action), the displays activate, but the machine is hung and the kernel panics a short time later. Both times it's happened, the machine was running X with the monitor attached and powered on. Once the monitor was "in use" (positioned with xrandr and showing part of the desktop). The other time, the monitor was plugged in to the DisplayPort and powered on, but not configured yet (it was simply displaying a mirror of what was on the laptop's display).

Details: this is a Lenovo Carbon X1 with Intel i915 video. This is with a recent 4.7 build. The crash.txt.X files the panic created are attached, and I have the other, larger crash files if needed.

This doesn't happen when no monitor is plugged into the DisplayPort. The machine can go to sleep and wake up reliably.


core.txt.0 (183 KB) core.txt.0 Happened when logged in and the monitor was configured with xrandr. cmusser, 07/28/2016 02:44 PM
core.txt.1 (180 KB) core.txt.1 Happened when monitor was plugged in, sitting at the XDM login screen. cmusser, 07/28/2016 02:44 PM



Updated by cmusser over 4 years ago

This continues to happen with later versions of the 4.7-era master branch (commit a798ebf2). However I have another system with an i915 (a Lenovo x220) that does not exhibit this lockup. This machine has a standard VGA connector, not a DisplayPort.


Updated by cmusser about 4 years ago

  • Status changed from New to Resolved

This works properly now. Both the x220 and X1 Carbon can be left plugged into an external monitor, allowed to blank the monitor after a period of inactivity and return to work without freezing when woken up.

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