[Intel-gfx] [PATCH] i915/oa: Simplify updating contexts

[Chris Wilson]

Quoting Tvrtko Ursulin (2018-09-13 09:54:15)
> 
> On 12/09/2018 16:50, Chris Wilson wrote:
> > By feeding a request, you ensure the reconfig is loaded again. +1 for
> > having it turn off when idle (and not instrument the kernel context at
> > all)!
> > 
> > Still I follow your logic that this should leave the oa config in
> > exactly the same state as before the patch, so
> > Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
> 
> Thanks, yeah, I am not sure excluding kernel context is possible. If I 
> understand the comments in i915_perf.c, and how much Lionel explained to 
> me, when on we want it on all the time so sampling timers are always on 
> regardless of context switches.

I was just thinking along the lines of not having the sampling active
when we are idle... But doesn't it actually break our powersaving model
entirely if the GT remains active after we drop our wakeref for it?
-Chris