[igt-dev] [PATCH i-g-t] i915/i915_pm_rpm: Only check for suspend failures after each debugfs entry

[Chris Wilson]

Quoting Martin Peres (2020-02-24 09:16:02)
> On 2020-02-21 15:56, Chris Wilson wrote:
> > Since we check before and then after each debugfs entry, we do not need
> > to check before each time as well. We will error out as soon as it does
> > fail, at all other times we know the system to be idle.
> > 
> > No impact on runtime for glk (which apparently is one of the better
> > behaving systems).
> > 
> > v2: Assert that we are currently suspended prior to opening the file,
> > i.e. that nothing else is waking up the device behind our backs.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Martin Peres <martin.peres at linux.intel.com>
> 
> This changes the purpose of this test, but checking that nothing is
> waking the driver in the background sound like a good test and could
> explain the terribly-slow runtime on some platforms!

Not really changing the underlying purpose, just removing the grace
window for the system to go to sleep by itself. If the system is waking
up behind our backs (hotplug? that we want to address and try to
capture).
-Chris