This particular issue has been covered in https://devtalk.nvidia.com/default/topic/595378/linux/ubuntu-13-10-nvidia-prime-suspend-resume-bug-touchpad-bug/2/?offset=22#4225154 before, however, that thread appears to be about two independent issues (as I do not experience the other one mentioned there). Thus, I decided to collect all available information about this, add my own findings, and make a thread specific to this behaviour.
This bug has also been covered in https://bugs.launchpad.net/ubuntu/+source/nvidia-prime/+bug/1220426, which lists other setups people have encountered it with.
The issue is that Xorg, when using the proprietary nvidia drivers, freezes irregularly, and can only be brought back by switching virtual terminals and then switching back. (e.g. Ctrl+Alt+F1 -> Ctrl+Alt+F7)
The issue only appears to occur on systems that use “ETPS/2 Elantech Touchpad” devices, and on those, only if the touchpad is in use. Freezes do not occur if the touchpad is not being touched or is disabled.
While it sounds like an issue specific to the touchpad, it’s not. It does not happen when using the Intel drivers (and with that the Intel GPU in the system). Furthermore, it does not appear to have been encountered in systems without an nvidia GPU.
The following laptop is the one I’m using, which does have the issue described in this thread:
Other laptop models with similar configuration reportedly show the same issue; they are mentioned in the launchpad bug report comments.
After/when the bug occurs, multiple xorg messages are logged, one of which is related to the touchpad. The relevant Xorg messages are reproduced below, as they have not been logged yet at the time at which nvidia-bug-report.sh was run. nvidia-bug-report.sh was run before switching back to the X11 VT.
[ 2864.405] (II) Open ACPI successful (/var/run/acpid.socket) [ 2864.405] (II) NVIDIA(0): Setting mode "NULL" [ 2864.405] (EE) NVIDIA(0): Failed to initiate mode change. [ 2864.405] (EE) NVIDIA(0): Failed to complete mode change [ 2864.433] (II) modesetting(G0): EDID vendor "CMN", prod id 4931 [ 2864.433] (II) modesetting(G0): Printing DDC gathered Modelines: [ 2864.433] (II) modesetting(G0): Modeline "1920x1080"x0.0 138.78 1920 1966 1996 2080 10 80 1082 1086 1112 -hsync -vsync (66.7 kHz eP) [ 2864.433] (II) modesetting(G0): Modeline "1920x1080"x0.0 92.52 1920 1966 1996 2080 10 80 1082 1086 1112 -hsync -vsync (44.5 kHz e) [ 2864.454] (--) synaptics: ETPS/2 Elantech Touchpad: touchpad found
The following graph shows that the issue does not occur while the computer is not being touched. The data collected comes from a period of seven days. The freezes were logged by grepping the Xorg log file for the above mentioned messages that are logged after it occurs, and ignoring the first two hits which are from boot-up. 325 freezes have been logged over the span of roughly 171 hours. This data has then been thrown in the general direction of a physics graduate, which resulted in a pretty graph.
Note the gaps on the timescale. This is when I’m asleep, and thus don’t touch the device, which appears to result in no freezes.
http://fratti.ch/tmp/nvidia-bug-report.log.gz - The nvidia-bug-report.sh output right after a freeze occurs, before switching back to the X11 VT.
Please let me know if I can provide any additional information to help fix this bug as soon as possible.