[Linux1394-cvslog] rev 527 - trunk

[SVN U. <hog...@us...>]

Author: hogsberg
Date: Wed, 17 Jul 2002 14:42:20 -0400
New Revision: 527

Modified:
   trunk/amdtp.c
Log:
Fix bug in start-on-cycle logic.


Modified: trunk/amdtp.c
==============================================================================
--- trunk/amdtp.c	(original)
+++ trunk/amdtp.c	Wed Jul 17 14:42:29 2002
@@ -333,18 +333,23 @@
 
 static void stream_start_dma(struct stream *s, struct packet_list *pl)
 {
-	u32 syt, cycle_count;
+	u32 syt_cycle, cycle_count, start_cycle;
 
 	cycle_count = reg_read(s->host->host->hostdata,
 			       OHCI1394_IsochronousCycleTimer) >> 12;
-	syt = be16_to_cpu(pl->packets[0].payload->syt) & 0x0f;
-	cycle_count = (cycle_count & ~0x0f) + 32 + syt;
-	if ((cycle_count & 0x1fff) >= 8000)
-		cycle_count = cycle_count - 8000 + 0x2000;
+	syt_cycle = (pl->last_cycle_count - PACKET_LIST_SIZE + 1) & 0x0f;
+
+	/* We program the DMA controller to start transmission at
+	 * least 17 cycles from now - this happens when the lower four
+	 * bits of cycle_count is 0x0f and syt_cycle is 0, in this
+	 * case the start cycle is cycle_count - 15 + 32. */
+	start_cycle = (cycle_count & ~0x0f) + 32 + syt_cycle;
+	if ((start_cycle & 0x1fff) >= 8000)
+		start_cycle = start_cycle - 8000 + 0x2000;
 
 	ohci1394_start_it_ctx(s->host->ohci, s->iso_context,
 			      pl->packets[0].db_bus, 3,
-			      cycle_count & 0x7fff);
+			      start_cycle & 0x7fff);
 }
 
 static void stream_put_dma_packet_list(struct stream *s,
@@ -744,13 +749,12 @@
 		       s->cycle_offset.integer) & 0xffff;
 		fraction_add(&s->cycle_offset, 
 			     &s->cycle_offset, &s->ticks_per_syt_offset);
-		if (s->cycle_offset.integer >= 3072) {
-			/* This next addition should be modulo 8000
-			 * (0x1f40), but we only use the lower 4 bits
-			 * of cycle_count, so we dont need the modulo. */
-			atomic_add(s->cycle_offset.integer / 3072, &s->cycle_count);
-			s->cycle_offset.integer %= 3072;
-		}
+
+		/* This next addition should be modulo 8000 (0x1f40),
+		 * but we only use the lower 4 bits of cycle_count, so
+		 * we dont need the modulo. */
+		atomic_add(s->cycle_offset.integer / 3072, &s->cycle_count);
+		s->cycle_offset.integer %= 3072;
 	}
 	else
 		syt = 0xffff;
@@ -891,7 +895,7 @@
 
 static int stream_configure(struct stream *s, int cmd, struct amdtp_ioctl *cfg)
 {
-	const int transfer_delay = 3000;
+	const int transfer_delay = 9000;
 
 	if (cfg->format <= AMDTP_FORMAT_IEC958_AC3)
 		s->format = cfg->format;