[Intel-gfx] [PATCH] drm/i915: WA: FBC Render Nuke.

[Rodrigo Vivi]

According BSPec: "Workaround: Do not enable Render Command Streamer tracking for FBC.
Instead insert a LRI to address 0x50380 with data 0x00000004 after the PIPE_CONTROL that
follows each render submission."

v2: Chris noticed that flush_domains check was missing here and also suggested to do
    LRI only when fbc is enabled. To avoid do a I915_READ on every flush lets use the
    module parameter check.

Cc: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at gmail.com>
---
 drivers/gpu/drm/i915/i915_reg.h         |  2 ++
 drivers/gpu/drm/i915/intel_pm.c         |  2 +-
 drivers/gpu/drm/i915/intel_ringbuffer.c | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index cc4c223..81ac584 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -977,6 +977,8 @@
 /* Framebuffer compression for Ivybridge */
 #define IVB_FBC_RT_BASE			0x7020
 
+#define MSG_FBC_REND_STATE	0x50380
+#define   FBC_REND_NUKE		(1<<2)
 
 #define _HSW_PIPE_SLICE_CHICKEN_1_A	0x420B0
 #define _HSW_PIPE_SLICE_CHICKEN_1_B	0x420B4
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 1879188..e830a9b 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -274,7 +274,7 @@ static void gen7_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
 	struct drm_i915_gem_object *obj = intel_fb->obj;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 
-	I915_WRITE(IVB_FBC_RT_BASE, obj->gtt_offset | ILK_FBC_RT_VALID);
+	I915_WRITE(IVB_FBC_RT_BASE, obj->gtt_offset);
 
 	if (!intel_edp_is_psr_enabled(dev))
 		I915_WRITE(ILK_DPFC_CONTROL, DPFC_CTL_EN | DPFC_CTL_LIMIT_1X |
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 3d2c236..905d372 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -280,6 +280,30 @@ gen7_render_ring_cs_stall_wa(struct intel_ring_buffer *ring)
 	return 0;
 }
 
+static int gen7_ring_fbc_flush(struct intel_ring_buffer *ring)
+{
+	struct drm_device *dev = ring->dev;
+	int ret;
+
+	if (i915_enable_fbc == 0)
+		return 0;
+
+	if (i915_enable_fbc < 0 && !IS_HASWELL(dev))
+		return 0;
+
+	ret = intel_ring_begin(ring, 4);
+	if (ret)
+		return ret;
+
+	intel_ring_emit(ring, MI_NOOP);
+	intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
+	intel_ring_emit(ring, MSG_FBC_REND_STATE);
+	intel_ring_emit(ring, FBC_REND_NUKE);
+	intel_ring_advance(ring);
+
+	return 0;
+}
+
 static int
 gen7_render_ring_flush(struct intel_ring_buffer *ring,
 		       u32 invalidate_domains, u32 flush_domains)
@@ -336,6 +360,9 @@ gen7_render_ring_flush(struct intel_ring_buffer *ring,
 	intel_ring_emit(ring, 0);
 	intel_ring_advance(ring);
 
+	if (flush_domains)
+		return gen7_ring_fbc_flush(ring);
+
 	return 0;
 }
 
@@ -1623,6 +1650,7 @@ gen6_ring_dispatch_execbuffer(struct intel_ring_buffer *ring,
 static int blt_ring_flush(struct intel_ring_buffer *ring,
 			  u32 invalidate, u32 flush)
 {
+	struct drm_device *dev = ring->dev;
 	uint32_t cmd;
 	int ret;
 
@@ -1645,6 +1673,10 @@ static int blt_ring_flush(struct intel_ring_buffer *ring,
 	intel_ring_emit(ring, 0);
 	intel_ring_emit(ring, MI_NOOP);
 	intel_ring_advance(ring);
+
+	if (IS_GEN7(dev))
+		return gen7_ring_fbc_flush(ring);
+
 	return 0;
 }
 
-- 
1.8.1.4