[PATCH] drm/i915/bdw: Do not initialize PPGTT in the legacy way for execlists

[PATCH] drm/i915/bdw: Do not initialize PPGTT in the legacy way for execlists

[Thomas Daniel]

A pending commit removes synchronous mode from switch_mm.  This breaks
execlists because switch_mm will always try to write to the legacy ring
buffer.

Return immediately from i915_ppgtt_init_gw in execlists mode.
No longer check for execlists mode in gen8_ppgtt_enable() because this
will no longer be called in execlists mode.

Signed-off-by: Thomas Daniel <thomas.daniel@intel.com>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 22ad38b..00267b3 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -777,12 +777,6 @@ static void gen8_ppgtt_enable(struct drm_device *dev)
 	struct intel_engine_cs *ring;
 	int j;
 
-	/* In the case of execlists, PPGTT is enabled by the context descriptor
-	 * and the PDPs are contained within the context itself.  We don't
-	 * need to do anything here. */
-	if (i915.enable_execlists)
-		return;
-
 	for_each_ring(ring, dev_priv, j) {
 		I915_WRITE(RING_MODE_GEN7(ring),
 			   _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));
@@ -1126,6 +1120,12 @@ int i915_ppgtt_init_hw(struct drm_device *dev)
 	struct i915_hw_ppgtt *ppgtt = dev_priv->mm.aliasing_ppgtt;
 	int i, ret = 0;
 
+	/* In the case of execlists, PPGTT is enabled by the context descriptor
+	 * and the PDPs are contained within the context itself.  We don't
+	 * need to do anything here. */
+	if (i915.enable_execlists)
+		return 0;
+
 	if (!USES_PPGTT(dev))
 		return 0;
 
-- 
1.7.9.5

Re: [PATCH] drm/i915/bdw: Do not initialize PPGTT in the legacy way for execlists

[Daniel Vetter]

On Wed, Aug 20, 2014 at 04:24:50PM +0100, Thomas Daniel wrote:
> A pending commit removes synchronous mode from switch_mm.  This breaks
> execlists because switch_mm will always try to write to the legacy ring
> buffer.
> 
> Return immediately from i915_ppgtt_init_gw in execlists mode.
> No longer check for execlists mode in gen8_ppgtt_enable() because this
> will no longer be called in execlists mode.
> 
> Signed-off-by: Thomas Daniel <thomas.daniel@intel.com>

Queued for -next, thanks for the patch.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch