[PATCH] drm/i915/gvt: Reduce rcs mocs switch latency

[Zhenyu Wang]

On 2017.10.30 14:19:15 +0800, changbin.du at intel.com wrote:
> From: Changbin Du <changbin.du at intel.com>
> 
> Use I915_WRITE_FW instead of I915_WRITE to reduce overhead.
> The overall mmio switch latency lowers from ~600us to ~180us.
> 
> Signed-off-by: Changbin Du <changbin.du at intel.com>
> ---
>  drivers/gpu/drm/i915/gvt/render.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/render.c b/drivers/gpu/drm/i915/gvt/render.c
> index e16c355..0672178 100644
> --- a/drivers/gpu/drm/i915/gvt/render.c
> +++ b/drivers/gpu/drm/i915/gvt/render.c
> @@ -209,7 +209,7 @@ static void load_mocs(struct intel_vgpu *vgpu, int ring_id)
>  	offset.reg = regs[ring_id];
>  	for (i = 0; i < 64; i++) {
>  		gen9_render_mocs[ring_id][i] = I915_READ_FW(offset);
> -		I915_WRITE(offset, vgpu_vreg(vgpu, offset));
> +		I915_WRITE_FW(offset, vgpu_vreg(vgpu, offset));
>  		offset.reg += 4;
>  	}
>  
> -- 

applied, thanks!

-- 
Open Source Technology Center, Intel ltd.

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