Commit ffe2a503 authored Oct 30, 2017 by Changbin Du Committed by Zhenyu Wang Nov 16, 2017

drm/i915/gvt: Reduce rcs mocs switch latency



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@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

parent 0bde438b

drivers/gpu/drm/i915/gvt/render.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;
		}