Ubuntu 15.10 freezes on Acer Aspire E11

I have successfully upgraded from Ubuntu 15.04 to Ubuntu 15.10 using do-release-upgrade on my Acer Aspire E11 laptop. However the whole computer freezes (i.e. gets unresponsive) after some minutes of work. It's impossible to switch to text screens and there is nothing in the logs.

• Windows is working well on the same machine, so perhaps there is a problem somewhere in Linux or its drivers.




• The problem is not caused by the system upgrade. The problem is there also on a fresh installation of 15.10.




• The problem is not caused by faulty RAM. The memtest86 was able to run successfully for 14 hours.




• The problem doesn't seem to be related to WiFi because it occurs even if WiFi is deactivated in the menu, i.e. Enable Wifi is unchecked.




• If Chromium browser is not running the system never freezes. How is it possible for the user-space application to block the whole system?




• The system freezes even if Chromium browser is not used, but it doesn't happen so often in this case.

Honestly I don't know how to debug such a situation. How to obtain useful information from a frozen system? What shall I look for? What to enable/disable? What to try?

I have been suffering freezes on my Acer E5-511 ever since 15.10, and upgraded to 16.04 2 weeks ago in the hope it would go away, but the problems continued, freeze every 10-30 min max ( and usually when moving the mouse strangely!).

I finally tried this 3 days ago in /etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux i8042.nopnp intel_idle.max_cstate=0 processor.max_cstate=1"

and have so far been crash free

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Updated by OP

The single required option is intel_idle.max_cstate=2 so the necessary modification of /etc/default/grub is:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_idle.max_cstate=2"

Perhaps the Acer Aspire E11 hardware is buggy, unable to wake up CPU from idle states higher than C2.