[Intel-gfx] [PATCH v4 4/4] drm/i915/perf: add a parameter to control the size of OA buffer

[Joonas Lahtinen]

Quoting Lionel Landwerlin (2018-10-23 13:07:07)
> The way our hardware is designed doesn't seem to let us use the
> MI_RECORD_PERF_COUNT command without setting up a circular buffer.
> 
> In the case where the user didn't request OA reports to be available
> through the i915 perf stream, we can set the OA buffer to the minimum
> size to avoid consuming memory which won't be used by the driver.
> 
> v2: Simplify oa buffer size exponent selection (Chris)
>     Reuse vma size field (Lionel)
> 
> v3: Restrict size opening parameter to values supported by HW (Chris)
> 
> v4: Drop out of date comment (Matt)
>     Add debug message when buffer size is rejected (Matt)
> 
> Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
> Reviewed-by: Matthew Auld <matthew.auld at intel.com>

For anything that alters the uAPI, please provide a link to the
userspace counterpart.

Regards, Joonas