[Intel-gfx] [PATCH] RFC/RFT drm/i915/oa: Drop aging-tail

[Lionel Landwerlin]

On 19/02/2019 10:28, Chris Wilson wrote:
> Switch to using coherent reads that are serialised with the register
> read to avoid the memory latency problem in favour over an arbitrary
> delay. The only zeroes seen during testing on HSW+ have been from
> configuration changes that do not update (therefore were truly zero
> entries and should be skipped).
>
> Signed-off-by: Chris Wilson<chris at chris-wilson.co.uk>
> Cc: Lionel Landwerlin<lionel.g.landwerlin at intel.com>
> Cc: Matthew Auld<matthew.auld at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_drv.h  |  59 ---
>   drivers/gpu/drm/i915/i915_perf.c | 625 +++++--------------------------
>   2 files changed, 87 insertions(+), 597 deletions(-)


Thanks,

I'll try i915_vma_pin_iomap() + I915_READ_FW() and see if the DRM_NOTE 
go away.

-Lionel