--- via82cxxx_audio.c.1.1.15	Thu Sep 20 15:41:30 2001
+++ via82cxxx_audio.c	Thu Sep 20 16:15:05 2001
@@ -12,10 +12,17 @@
  * the driver's Website at
  * http://gtf.org/garzik/drivers/via82cxxx/
  *
+ * Thomas Sailer, 2001-09-20:
+ *   - unlock syscall_sem during sleeping in read/write
+ *   - return byte count in case of partial transfer instead of
+ *     error in read/write syscalls
+ *   - avoid loosing wake_up event
+ *   - nonblocking semaphore down disabled
+ *
  */
 
 
-#define VIA_VERSION	"1.1.15"
+#define VIA_VERSION	"1.1.15tsa"
 
 
 #include <linux/config.h>
@@ -459,6 +466,14 @@
 
 static inline int via_syscall_down (struct via_info *card, int nonblock)
 {
+	/* Thomas Sailer:
+	 * EAGAIN is supposed to be used if IO is pending,
+	 * not if there is contention on some internal
+	 * synchronization primitive which should be
+	 * held only for a short time anyway
+	 */
+	nonblock = 0;
+
 	if (nonblock) {
 		if (down_trylock (&card->syscall_sem))
 			return -EAGAIN;
@@ -1973,18 +1988,27 @@
 				char *userbuf, size_t count,
 				int nonblock)
 {
+        DECLARE_WAITQUEUE(wait, current);
 	const char *orig_userbuf = userbuf;
 	struct via_channel *chan = &card->ch_in;
 	size_t size;
 	int n, tmp;
+	ssize_t ret = 0;
 
 	/* if SGD has not yet been started, start it */
 	via_chan_maybe_start (chan);
 
 handle_one_block:
 	/* just to be a nice neighbor */
-	if (current->need_resched)
+	/* Thomas Sailer:
+	 * But also to ourselves, release semaphore if we do so */
+	if (current->need_resched) {
+		up(&card->syscall_sem);
 		schedule ();
+		ret = via_syscall_down (card, nonblock);
+		if (ret)
+			goto out;
+	}
 
 	/* grab current channel software pointer.  In the case of
 	 * recording, this is pointing to the next buffer that
@@ -1996,21 +2020,37 @@
 	 * to be copied to userland.  sleep until at least
 	 * one buffer has been read from the audio hardware.
 	 */
-	tmp = atomic_read (&chan->n_frags);
-	assert (tmp >= 0);
-	assert (tmp <= chan->frag_number);
-	while (tmp == 0) {
-		if (nonblock || !chan->is_active)
-			return -EAGAIN;
+	add_wait_queue(&chan->wait, &wait);
+	for (;;) {
+		__set_current_state(TASK_INTERRUPTIBLE);
+		tmp = atomic_read (&chan->n_frags);
+		assert (tmp >= 0);
+		assert (tmp <= chan->frag_number);
+		if (tmp)
+			break;
+		if (nonblock || !chan->is_active) {
+			ret = -EAGAIN;
+			break;
+		}
+
+		up(&card->syscall_sem);
 
 		DPRINTK ("Sleeping on block %d\n", n);
-		interruptible_sleep_on (&chan->wait);
+		schedule();
 
-		if (signal_pending (current))
-			return -ERESTARTSYS;
+		ret = via_syscall_down (card, nonblock);
+		if (ret)
+			break;
 
-		tmp = atomic_read (&chan->n_frags);
+		if (signal_pending (current)) {
+			ret = -ERESTARTSYS;
+			break;
+		}
 	}
+        set_current_state(TASK_RUNNING);
+        remove_wait_queue(&chan->wait, &wait);
+	if (ret)
+		goto out;
 
 	/* Now that we have a buffer we can read from, send
 	 * as much as sample data possible to userspace.
@@ -2021,8 +2061,10 @@
 		size = (count < slop_left) ? count : slop_left;
 		if (copy_to_user (userbuf,
 				  chan->pgtbl[n / (PAGE_SIZE / chan->frag_size)].cpuaddr + n % (PAGE_SIZE / chan->frag_size) + chan->slop_len,
-				  size))
-			return -EFAULT;
+				  size)) {
+			ret = -EFAULT;
+			goto out;
+		}
 
 		count -= size;
 		chan->slop_len += size;
@@ -2071,7 +2113,7 @@
 		goto handle_one_block;
 
 out:
-	return userbuf - orig_userbuf;
+	return (userbuf != orig_userbuf) ? (userbuf - orig_userbuf) : ret;
 }
 
 
@@ -2122,16 +2164,25 @@
 				 const char *userbuf, size_t count,
 				 int nonblock)
 {
+        DECLARE_WAITQUEUE(wait, current);
 	const char *orig_userbuf = userbuf;
 	struct via_channel *chan = &card->ch_out;
 	volatile struct via_sgd_table *sgtable = chan->sgtable;
 	size_t size;
 	int n, tmp;
+	ssize_t ret = 0;
 
 handle_one_block:
 	/* just to be a nice neighbor */
-	if (current->need_resched)
+	/* Thomas Sailer:
+	 * But also to ourselves, release semaphore if we do so */
+	if (current->need_resched) {
+		up(&card->syscall_sem);
 		schedule ();
+		ret = via_syscall_down (card, nonblock);
+		if (ret)
+			goto out;
+	}
 
 	/* grab current channel fragment pointer.  In the case of
 	 * playback, this is pointing to the next fragment that
@@ -2143,21 +2194,37 @@
 	 * to be filled by userspace.  Sleep until
 	 * at least one fragment is available for our use.
 	 */
-	tmp = atomic_read (&chan->n_frags);
-	assert (tmp >= 0);
-	assert (tmp <= chan->frag_number);
-	while (tmp == 0) {
-		if (nonblock || !chan->is_enabled)
-			return -EAGAIN;
+	add_wait_queue(&chan->wait, &wait);
+	for (;;) {
+		__set_current_state(TASK_INTERRUPTIBLE);
+		tmp = atomic_read (&chan->n_frags);
+		assert (tmp >= 0);
+		assert (tmp <= chan->frag_number);
+		if (tmp)
+			break;
+		if (nonblock || !chan->is_active) {
+			ret = -EAGAIN;
+			break;
+		}
+
+		up(&card->syscall_sem);
 
 		DPRINTK ("Sleeping on page %d, tmp==%d, ir==%d\n", n, tmp, chan->is_record);
-		interruptible_sleep_on (&chan->wait);
+		schedule();
 
-		if (signal_pending (current))
-			return -ERESTARTSYS;
+		ret = via_syscall_down (card, nonblock);
+		if (ret)
+			break;
 
-		tmp = atomic_read (&chan->n_frags);
+		if (signal_pending (current)) {
+			ret = -ERESTARTSYS;
+			break;
+		}
 	}
+        set_current_state(TASK_RUNNING);
+        remove_wait_queue(&chan->wait, &wait);
+	if (ret)
+		goto out;
 
 	/* Now that we have at least one fragment we can write to, fill the buffer
 	 * as much as possible with data from userspace.
@@ -2167,8 +2234,10 @@
 
 		size = (count < slop_left) ? count : slop_left;
 		if (copy_from_user (chan->pgtbl[n / (PAGE_SIZE / chan->frag_size)].cpuaddr + (n % (PAGE_SIZE / chan->frag_size)) * chan->frag_size + chan->slop_len,
-				    userbuf, size))
-			return -EFAULT;
+				    userbuf, size)) {
+			ret = -EFAULT;
+			goto out;
+		}
 
 		count -= size;
 		chan->slop_len += size;
@@ -2330,6 +2399,9 @@
 static int via_dsp_drain_playback (struct via_info *card,
 				   struct via_channel *chan, int nonblock)
 {
+        DECLARE_WAITQUEUE(wait, current);
+	int ret = 0;
+
 	DPRINTK ("ENTER, nonblock = %d\n", nonblock);
 
 	if (chan->slop_len > 0)
@@ -2340,10 +2412,16 @@
 
 	via_chan_maybe_start (chan);
 
-	while (atomic_read (&chan->n_frags) < chan->frag_number) {
+	add_wait_queue(&chan->wait, &wait);
+	for (;;) {
+		__set_current_state(TASK_INTERRUPTIBLE);
+		if (atomic_read (&chan->n_frags) >= chan->frag_number)
+			break;
+
 		if (nonblock) {
 			DPRINTK ("EXIT, returning -EAGAIN\n");
-			return -EAGAIN;
+			ret = -EAGAIN;
+			break;
 		}
 
 #ifdef VIA_DEBUG
@@ -2372,14 +2450,24 @@
 			printk (KERN_ERR "sleeping but not active\n");
 #endif
 
+		up(&card->syscall_sem);
+
 		DPRINTK ("sleeping, nbufs=%d\n", atomic_read (&chan->n_frags));
-		interruptible_sleep_on (&chan->wait);
+		schedule();
+
+		if ((ret = via_syscall_down (card, nonblock)))
+			break;
 
 		if (signal_pending (current)) {
 			DPRINTK ("EXIT, returning -ERESTARTSYS\n");
-			return -ERESTARTSYS;
+			ret = -ERESTARTSYS;
+			break;
 		}
 	}
+        set_current_state(TASK_RUNNING);
+        remove_wait_queue(&chan->wait, &wait);
+	if (ret)
+		return ret;
 
 #ifdef VIA_DEBUG
 	{
@@ -2408,7 +2496,7 @@
 
 out:
 	DPRINTK ("EXIT, returning 0\n");
-	return 0;
+	return ret;
 }