From 676d2643a732b489bf2d7995d58e2bc9f472b088 Mon Sep 17 00:00:00 2001
From: Ben Widawsky <ben@bwidawsk.net>
Date: Mon, 4 Jun 2012 14:42:48 -0700
Subject: [PATCH] drm/i915: Ivybridge MI_ARB_ON_OFF context w/a
The workaround itself applies to gen7 only (according to the docs) and
as Eric Anholt points out shouldn't be required since we don't use HW
scheduling features, and therefore arbitration. Though since it is a
small, and simple addition, and we don't really understand the issue,
just do it.
FWIW, I eventually want to play with some of the arbitration stuff, and
I'd hate to forget about this.
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
---
drivers/gpu/drm/i915/i915_gem_context.c | 12 +++++++++++-
drivers/gpu/drm/i915/i915_reg.h | 3 +++
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index fb6aa5e10991d..d49d5fc0a592f 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -324,10 +324,15 @@ mi_set_context(struct intel_ring_buffer *ring,
{
int ret;
- ret = intel_ring_begin(ring, 4);
+ ret = intel_ring_begin(ring, 6);
if (ret)
return ret;
+ if (IS_GEN7(ring->dev))
+ intel_ring_emit(ring, MI_ARB_ON_OFF | MI_ARB_DISABLE);
+ else
+ intel_ring_emit(ring, MI_NOOP);
+
intel_ring_emit(ring, MI_NOOP);
intel_ring_emit(ring, MI_SET_CONTEXT);
intel_ring_emit(ring, new_context->obj->gtt_offset |
@@ -338,6 +343,11 @@ mi_set_context(struct intel_ring_buffer *ring,
/* w/a: MI_SET_CONTEXT must always be followed by MI_NOOP */
intel_ring_emit(ring, MI_NOOP);
+ if (IS_GEN7(ring->dev))
+ intel_ring_emit(ring, MI_ARB_ON_OFF | MI_ARB_ENABLE);
+ else
+ intel_ring_emit(ring, MI_NOOP);
+
intel_ring_advance(ring);
return ret;
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index bee1012081955..14cb714df352d 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -210,6 +210,9 @@
#define MI_DISPLAY_FLIP MI_INSTR(0x14, 2)
#define MI_DISPLAY_FLIP_I915 MI_INSTR(0x14, 1)
#define MI_DISPLAY_FLIP_PLANE(n) ((n) << 20)
+#define MI_ARB_ON_OFF MI_INSTR(0x08, 0)
+#define MI_ARB_ENABLE (1<<0)
+#define MI_ARB_DISABLE (0<<0)
#define MI_SET_CONTEXT MI_INSTR(0x18, 0)
#define MI_MM_SPACE_GTT (1<<8)
#define MI_MM_SPACE_PHYSICAL (0<<8)
--
2.39.5