1 files changed, 53 insertions, 6 deletions

diff --git a/drivers/char/drm/via_dma.c b/drivers/char/drm/via_dma.c
index 94baec692b57..7a339dba6a69 100644
--- a/drivers/char/drm/via_dma.c
+++ b/drivers/char/drm/via_dma.c
@@ -126,6 +126,8 @@ via_cmdbuf_wait(drm_via_private_t * dev_priv, unsigned int size)
 			     hw_addr, cur_addr, next_addr);
 			return -1;
 		}
+		if  ((cur_addr < hw_addr) && (next_addr >= hw_addr))
+			msleep(1);
 	} while ((cur_addr < hw_addr) && (next_addr >= hw_addr));
 	return 0;
 }
@@ -416,27 +418,50 @@ static int via_hook_segment(drm_via_private_t * dev_priv,
 	int paused, count;
 	volatile uint32_t *paused_at = dev_priv->last_pause_ptr;
 	uint32_t reader,ptr;
+	uint32_t diff;
 
 	paused = 0;
 	via_flush_write_combine();
 	(void) *(volatile uint32_t *)(via_get_dma(dev_priv) -1);
+
 	*paused_at = pause_addr_lo;
 	via_flush_write_combine();
 	(void) *paused_at;
+
 	reader = *(dev_priv->hw_addr_ptr);
 	ptr = ((volatile char *)paused_at - dev_priv->dma_ptr) +
 		dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr + 4;
+
 	dev_priv->last_pause_ptr = via_get_dma(dev_priv) - 1;
 
-	if ((ptr - reader) <= dev_priv->dma_diff ) {
-		count = 10000000;
-		while (!(paused = (VIA_READ(0x41c) & 0x80000000)) && count--);
+	/*
+	 * If there is a possibility that the command reader will 
+	 * miss the new pause address and pause on the old one,
+	 * In that case we need to program the new start address
+	 * using PCI.
+	 */
+
+	diff = (uint32_t) (ptr - reader) - dev_priv->dma_diff;
+	count = 10000000;
+	while(diff == 0 && count--) {
+		paused = (VIA_READ(0x41c) & 0x80000000);
+		if (paused) 
+			break;
+		reader = *(dev_priv->hw_addr_ptr);
+		diff = (uint32_t) (ptr - reader) - dev_priv->dma_diff;
 	}
 
+	paused = VIA_READ(0x41c) & 0x80000000;
+
 	if (paused && !no_pci_fire) {
 		reader = *(dev_priv->hw_addr_ptr);
-		if ((ptr - reader) == dev_priv->dma_diff) {
-
+		diff = (uint32_t) (ptr - reader) - dev_priv->dma_diff;
+		diff &= (dev_priv->dma_high - 1);
+		if (diff != 0 && diff < (dev_priv->dma_high >> 1)) {
+			DRM_ERROR("Paused at incorrect address. "
+				  "0x%08x, 0x%08x 0x%08x\n",
+				  ptr, reader, dev_priv->dma_diff);
+		} else if (diff == 0) {
 			/*
 			 * There is a concern that these writes may stall the PCI bus
 			 * if the GPU is not idle. However, idling the GPU first
@@ -577,6 +602,7 @@ static void via_cmdbuf_jump(drm_via_private_t * dev_priv)
 	uint32_t pause_addr_lo, pause_addr_hi;
 	uint32_t jump_addr_lo, jump_addr_hi;
 	volatile uint32_t *last_pause_ptr;
+	uint32_t dma_low_save1, dma_low_save2;
 
 	agp_base = dev_priv->dma_offset + (uint32_t) dev_priv->agpAddr;
 	via_align_cmd(dev_priv, HC_HAGPBpID_JUMP, 0, &jump_addr_hi,
@@ -603,8 +629,29 @@ static void via_cmdbuf_jump(drm_via_private_t * dev_priv)
 		      &pause_addr_lo, 0);
 
 	*last_pause_ptr = pause_addr_lo;
+	dma_low_save1 = dev_priv->dma_low;
 
-	via_hook_segment( dev_priv, jump_addr_hi, jump_addr_lo, 0);
+	/*
+	 * Now, set a trap that will pause the regulator if it tries to rerun the old
+	 * command buffer. (Which may happen if via_hook_segment detecs a command regulator pause
+	 * and reissues the jump command over PCI, while the regulator has already taken the jump
+	 * and actually paused at the current buffer end).
+	 * There appears to be no other way to detect this condition, since the hw_addr_pointer
+	 * does not seem to get updated immediately when a jump occurs.
+	 */
+
+	last_pause_ptr =
+		via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0, &pause_addr_hi,
+			      &pause_addr_lo, 0) - 1;
+	via_align_cmd(dev_priv, HC_HAGPBpID_PAUSE, 0, &pause_addr_hi,
+		      &pause_addr_lo, 0);
+	*last_pause_ptr = pause_addr_lo;
+
+	dma_low_save2 = dev_priv->dma_low;
+	dev_priv->dma_low = dma_low_save1;
+	via_hook_segment(dev_priv, jump_addr_hi, jump_addr_lo, 0);
+	dev_priv->dma_low = dma_low_save2;
+	via_hook_segment(dev_priv, pause_addr_hi, pause_addr_lo, 0);
 }