Chris Wilson authored Mar 02, 2018 and Tvrtko Ursulin committed Mar 05, 2018

CPU hotplug, especially CPU0, can be flaky on commodity hardware.

To improve test reliability and reponse times when testing larger runs we
need to handle those cases better.

Handle failures to off-line a CPU by immediately skipping the test, and
failures to on-line a CPU by immediately rebooting the machine.

This patch includes igt_sysrq_reboot implementation from Chris Wilson.

v2: Halt by default, reboot if env variable IGT_REBOOT_ON_FATAL_ERROR is
    set. (Petri Latvala)

v3: Add missign docs and update stale comment. (Petri Latvala)

v4: Use pause instead of sleep. (Chris Wilson)
v5: Newlines! (Chris Wilson)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Petri Latvala <petri.latvala@intel.com>
Cc: Tomi Sarvela <tomi.p.sarvela@intel.com>
Reviewed-by: Petri Latvala <petri.latvala@intel.com>