[Intel-gfx] [PATCH v7 06/11] drm/i915: Enable i915 perf stream for Haswell OA unit

[Chris Wilson]

On Wed, Oct 26, 2016 at 12:51:58AM +0100, Robert Bragg wrote:
>    On Tue, Oct 25, 2016 at 10:35 PM, Matthew Auld
>    <[1]matthew.william.auld at gmail.com> wrote:
> 
>      On 25 October 2016 at 00:19, Robert Bragg <[2]robert at sixbynine.org>
>      wrote:
> 
>     
> 
>      > diff --git a/drivers/gpu/drm/i915/i915_drv.h
>      b/drivers/gpu/drm/i915/i915_drv.h
>      > index 3448d05..ea24814 100644
>      > --- a/drivers/gpu/drm/i915/i915_drv.h
>      > +++ b/drivers/gpu/drm/i915/i915_drv.h
>      > @@ -1764,6 +1764,11 @@ struct intel_wm_config {
> 
>      >
>      >  struct drm_i915_private {
>      > @@ -2149,16 +2164,46 @@ struct drm_i915_private {
>      >
>      >         struct {
>      >                 bool initialized;
>      > +
>      >                 struct mutex lock;
>      >                 struct list_head streams;
>      >
>      > +               spinlock_t hook_lock;
>      > +
>      >                 struct {
>      > -                       u32 metrics_set;
>      > +                       struct i915_perf_stream *exclusive_stream;
>      > +
>      > +                       u32 specific_ctx_id;
>      Can we just get rid of this, now that the vma remains pinned we can
>      simply get the ggtt address at the time of configuring the OA_CONTROL
>      register ?
> 
>    I considered that, but would ideally prefer to keep it considering the
>    gen8+ patches to come. For gen8+ (with execlists) the context ID isn't a
>    gtt offset.

In terms of symmetry, keeping the vma you pinned and unpinning the same
later makes its ownership much clearer. (And I do want the owner of each
pin to be clear, for when we start enabling debug to catch the VMA
leaks.)
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre