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[0040/1094] drm/i915: Remove extraneous mm_switch in ppgtt enable

Message ID 1413889294-31328-41-git-send-email-dheerajx.s.jamwal@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Dheeraj Jamwal Oct. 21, 2014, 10:44 a.m. UTC 
From: Ben Widawsky <benjamin.widawsky@intel.com>

Originally this commit message said:
Now that do_switch does the mm switch, and we always enable the aliasing
PPGTT, and contexts at the same time, there is no need to continue doing
this during PPGTT enabling.

Since originally writing the patch however, I introduced the concept of
synchronous mm switching (using MMIO). Since this is generally not
recommended in the spec (for reasons unknown), I've isolated its usage
as much as possible. As such the "extraneous" switch only ever will
occur when we have full PPGTT.

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
(cherry picked from commit d2ff7192f3cd77fcace0adf99a47ff5e30d6e0d3)

Signed-off-by: Dheeraj Jamwal <dheerajx.s.jamwal@intel.com>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c |   14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index b84d128..9bf5960 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -612,6 +612,12 @@  static int gen8_ppgtt_enable(struct i915_hw_ppgtt *ppgtt)
 	for_each_ring(ring, dev_priv, j) {
 		I915_WRITE(RING_MODE_GEN7(ring),
 			   _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));
+
+		/* We promise to do a switch later with FULL PPGTT. If this is
+		 * aliasing, this is the one and only switch we'll do */
+		if (USES_FULL_PPGTT(dev))
+			continue;
+
 		ret = ppgtt->switch_mm(ppgtt, ring, true);
 		if (ret)
 			goto err_out;
@@ -651,11 +657,17 @@  static int gen7_ppgtt_enable(struct i915_hw_ppgtt *ppgtt)
 		/* GFX_MODE is per-ring on gen7+ */
 		I915_WRITE(RING_MODE_GEN7(ring),
 			   _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));
+
+		/* We promise to do a switch later with FULL PPGTT. If this is
+		 * aliasing, this is the one and only switch we'll do */
+		if (USES_FULL_PPGTT(dev))
+			continue;
+
 		ret = ppgtt->switch_mm(ppgtt, ring, true);
 		if (ret)
 			return ret;
-
 	}
+
 	return 0;
 }