[Intel-gfx] [PATCH v6 06/11] drm/i915: Enable i915 perf stream for Haswell OA unit

[Robert Bragg]

On Thu, Oct 20, 2016 at 11:10 PM, Chris Wilson <chris at chris-wilson.co.uk>
wrote:

> On Thu, Oct 20, 2016 at 10:19:05PM +0100, Robert Bragg wrote:
> > +int i915_gem_context_pin_legacy_rcs_state(struct drm_i915_private
> *dev_priv,
> > +                                       struct i915_gem_context *ctx,
> > +                                       u64 flags)
>
> This is still no.
>

Okay, but it's a little frustrating for me to go in circles here :-/

I didn't originally do it this way; I originally looked at pinning the
context when opening the stream so I didn't have to consider it being
relocated. The feedback from Daniel Vetter was to look at doing it this way
I think because of some concern to do with some shrinker corner cases.

... just dug up the archive:
https://lists.freedesktop.org/archives/intel-gfx/2014-November/055385.html

Can you maybe please explain what's wrong with the current approach and
provide some justification for a different approach with some reassurance
that Daniel's original concern with the shrinker unpinning contexts isn't
actually a problem? I don't currently understand the concern with this, and
this approach seems to have been working well for quite a long time now.

- Robert
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