Avoid unnecessary waits for command regulator pause.

diff --git a/shared-core/via_dma.c b/shared-core/via_dma.c
index ffdb7bf..9f58bfa 100644 (file)
--- a/shared-core/via_dma.c
+++ b/shared-core/via_dma.c
@@ -113,6 +113,8 @@ 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;
 }
@@ -406,6 +408,7 @@ 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();
@@ -421,14 +424,26 @@ static int via_hook_segment(drm_via_private_t * dev_priv,
 
        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) {
-               uint32_t diff;
                reader = *(dev_priv->hw_addr_ptr);
                diff = (uint32_t) (ptr - reader) - dev_priv->dma_diff;
                diff &= (dev_priv->dma_high - 1);