From: Michel Dänzer <michel@tungstengraphics.com>
Date: Fri, 15 Jun 2007 15:13:11 +0000 (+0200)
Subject: i915: Fix handling of breadcrumb counter wraparounds.
X-Git-Tag: libdrm-2.3.1~183^2~270
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=3d5d41fa9823cf44138c8f4bc954bca80539d74e;p=platform%2Fupstream%2Flibdrm.git

i915: Fix handling of breadcrumb counter wraparounds.
---

diff --git a/linux-core/i915_drv.c b/linux-core/i915_drv.c
index 4c35b4c..4943706 100644
--- a/linux-core/i915_drv.c
+++ b/linux-core/i915_drv.c
@@ -41,9 +41,9 @@ static struct pci_device_id pciidlist[] = {
 #ifdef I915_HAVE_FENCE
 static drm_fence_driver_t i915_fence_driver = {
 	.num_classes = 1,
-	.wrap_diff = (1 << 30),
-	.flush_diff = (1 << 29),
-	.sequence_mask = 0x7fffffffU,
+	.wrap_diff = (1U << (BREADCRUMB_BITS - 1)),
+	.flush_diff = (1U << (BREADCRUMB_BITS - 2)),
+	.sequence_mask = BREADCRUMB_MASK,
 	.lazy_capable = 1,
 	.emit = i915_fence_emit_sequence,
 	.poke_flush = i915_poke_flush,
diff --git a/linux-core/i915_fence.c b/linux-core/i915_fence.c
index 88daa57..0087348 100644
--- a/linux-core/i915_fence.c
+++ b/linux-core/i915_fence.c
@@ -61,7 +61,7 @@ static void i915_perform_flush(drm_device_t * dev)
 		 * First update fences with the current breadcrumb.
 		 */
 
-		diff = sequence - fc->last_exe_flush;
+		diff = (sequence - fc->last_exe_flush) & BREADCRUMB_MASK;
 		if (diff < driver->wrap_diff && diff != 0) {
 			drm_fence_handler(dev, 0, sequence, DRM_FENCE_TYPE_EXE);
 		}
diff --git a/shared-core/i915_dma.c b/shared-core/i915_dma.c
index ebb184c..dbc5f95 100644
--- a/shared-core/i915_dma.c
+++ b/shared-core/i915_dma.c
@@ -445,10 +445,12 @@ void i915_emit_breadcrumb(drm_device_t *dev)
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	RING_LOCALS;
 
-	dev_priv->sarea_priv->last_enqueue = ++dev_priv->counter;
+	if (++dev_priv->counter > BREADCRUMB_MASK) {
+		 dev_priv->counter = 1;
+		 DRM_DEBUG("Breadcrumb counter wrapped around\n");
+	}
 
-	if (dev_priv->counter > 0x7FFFFFFFUL)
-		 dev_priv->sarea_priv->last_enqueue = dev_priv->counter = 1;
+	dev_priv->sarea_priv->last_enqueue = dev_priv->counter;
 
 	BEGIN_LP_RING(4);
 	OUT_RING(CMD_STORE_DWORD_IDX);
diff --git a/shared-core/i915_drv.h b/shared-core/i915_drv.h
index 9deee8e..e043299 100644
--- a/shared-core/i915_drv.h
+++ b/shared-core/i915_drv.h
@@ -363,6 +363,9 @@ extern int i915_wait_ring(drm_device_t * dev, int n, const char *caller);
 
 #define CMD_OP_DESTBUFFER_INFO	 ((0x3<<29)|(0x1d<<24)|(0x8e<<16)|1)
 
+#define BREADCRUMB_BITS 31
+#define BREADCRUMB_MASK ((1U << BREADCRUMB_BITS) - 1)
+
 #define READ_BREADCRUMB(dev_priv)  (((volatile u32*)(dev_priv->hw_status_page))[5])
 #define READ_HWSP(dev_priv, reg)  (((volatile u32*)(dev_priv->hw_status_page))[reg])
 #endif