[Intel-gfx] [PATCH 3/7] drm/i915/vlv: Not reallocating VLV PCTX upon every suspend/resume

[akash.goel at intel.com]

From: Akash Goel <akash.goel at intel.com>

VLV PCTX will come from stolen memory. Upon every suspend/resume cycle,
this is being deallocated/reallocated. Given that PCTX has to be there
at a constant stolen memory offset, doing this is not required. Also
there is a chance of it getting corrupted, if this range gets used for
some other allocation(on resume), which can result in GPU hangs.

Signed-off-by: Akash Goel <akash.goel at intel.com>
---
 drivers/gpu/drm/i915/i915_gem_stolen.c | 5 +++++
 drivers/gpu/drm/i915/intel_pm.c        | 9 ++++-----
 2 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
index 29b3693..5cf97d6 100644
--- a/drivers/gpu/drm/i915/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
@@ -213,6 +213,11 @@ void i915_gem_cleanup_stolen(struct drm_device *dev)
 	if (!drm_mm_initialized(&dev_priv->mm.stolen))
 		return;
 
+	if (dev_priv->vlv_pctx) {
+		drm_gem_object_unreference(&dev_priv->vlv_pctx->base);
+		dev_priv->vlv_pctx = NULL;
+	}
+
 	i915_gem_stolen_cleanup_compression(dev);
 	drm_mm_takedown(&dev_priv->mm.stolen);
 }
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 469170c..369cc73 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -3138,11 +3138,6 @@ static void valleyview_disable_rps(struct drm_device *dev)
 	I915_WRITE(GEN6_RC_CONTROL, 0);
 
 	gen6_disable_rps_interrupts(dev);
-
-	if (dev_priv->vlv_pctx) {
-		drm_gem_object_unreference(&dev_priv->vlv_pctx->base);
-		dev_priv->vlv_pctx = NULL;
-	}
 }
 
 static void intel_print_rc6_info(struct drm_device *dev, u32 mode)
@@ -3508,6 +3503,10 @@ static void valleyview_setup_pctx(struct drm_device *dev)
 	u32 pcbr;
 	int pctx_size = 24*1024;
 
+	/* If PC Context is already there, then bail out*/
+	if (dev_priv->vlv_pctx)
+		return;
+
 	pcbr = I915_READ(VLV_PCBR);
 	if (pcbr) {
 		/* BIOS set it up already, grab the pre-alloc'd space */
-- 
1.8.5.2