--- drivers/sound/maestro.c.old	Tue Jun  5 21:21:43 2001
+++ drivers/sound/maestro.c	Tue Jun  5 23:44:41 2001
@@ -431,6 +431,7 @@
 
 	/* pointer to each dsp?s piece of the apu->src buffer page */
 	void *mixbuf;
+	struct semaphore sem;
 
 };
 	
@@ -2258,7 +2259,7 @@
 ess_read(struct file *file, char *buffer, size_t count, loff_t *ppos)
 {
 	struct ess_state *s = (struct ess_state *)file->private_data;
-	ssize_t ret;
+	ssize_t ret = 0; 
 	unsigned long flags;
 	unsigned swptr;
 	int cnt;
@@ -2269,13 +2270,13 @@
 		return -ESPIPE;
 	if (s->dma_adc.mapped)
 		return -ENXIO;
-	if (!s->dma_adc.ready && (ret = prog_dmabuf(s, 1)))
-		return ret;
 	if (!access_ok(VERIFY_WRITE, buffer, count))
 		return -EFAULT;
 	if(!(combbuf = kmalloc(count,GFP_KERNEL)))
 		return -ENOMEM;
-	ret = 0;
+	down(&s->sem);	
+	if (!s->dma_adc.ready && (ret = prog_dmabuf(s, 1)))
+		goto rec_return_free;
 
 	calc_bob_rate(s);
 
@@ -2298,9 +2299,10 @@
 			start_adc(s);
 			if (file->f_flags & O_NONBLOCK) 
 			{
-				ret = ret ? ret : -EAGAIN;
+				if(!ret) ret = -EAGAIN;
 				goto rec_return_free;
 			}
+			up(&s->sem);
 			if (!interruptible_sleep_on_timeout(&s->dma_adc.wait, HZ)) {
 				if(! s->card->in_suspend) printk(KERN_DEBUG "maestro: read: chip lockup? dmasz %u fragsz %u count %i hwptr %u swptr %u\n",
 				       s->dma_adc.dmasize, s->dma_adc.fragsize, s->dma_adc.count, 
@@ -2317,7 +2319,13 @@
 			}
 			if (signal_pending(current)) 
 			{
-				ret = ret ? ret : -ERESTARTSYS;
+				if(!ret) ret = -ERESTARTSYS;
+				goto rec_return_free;
+			}
+			down(&s->sem);
+			if (s->dma_adc.mapped)
+			{
+				ret = -ENXIO;
 				goto rec_return_free;
 			}
 			continue;
@@ -2327,12 +2335,12 @@
 			/* swptr/2 so that we know the real offset in each apu's buffer */
 			comb_stereo(s->dma_adc.rawbuf,combbuf,swptr/2,cnt,s->dma_adc.dmasize);
 			if (copy_to_user(buffer, combbuf, cnt)) {
-				ret = ret ? ret : -EFAULT;
+				if(!ret) ret = -EFAULT;
 				goto rec_return_free;
 			}
 		} else  {
 			if (copy_to_user(buffer, s->dma_adc.rawbuf + swptr, cnt)) {
-				ret = ret ? ret : -EFAULT;
+				if(!ret) ret = -EFAULT;
 				goto rec_return_free;
 			}
 		}
@@ -2349,6 +2357,7 @@
 	}
 
 rec_return_free:
+	up(&s->sem);
 	if(combbuf) kfree(combbuf);
 	return ret;
 }
@@ -2367,10 +2376,11 @@
 		return -ESPIPE;
 	if (s->dma_dac.mapped)
 		return -ENXIO;
-	if (!s->dma_dac.ready && (ret = prog_dmabuf(s, 0)))
-		return ret;
 	if (!access_ok(VERIFY_READ, buffer, count))
 		return -EFAULT;
+	down(&s->sem);
+	if (!s->dma_dac.ready && (ret = prog_dmabuf(s, 0)))
+		goto return_free;
 	ret = 0;
 
 	calc_bob_rate(s);
@@ -2400,6 +2410,7 @@
 				if(!ret) ret = -EAGAIN;
 				goto return_free;
 			}
+			up(&s->sem);
 			if (!interruptible_sleep_on_timeout(&s->dma_dac.wait, HZ)) {
 				if(! s->card->in_suspend) printk(KERN_DEBUG "maestro: write: chip lockup? dmasz %u fragsz %u count %i hwptr %u swptr %u\n",
 				       s->dma_dac.dmasize, s->dma_dac.fragsize, s->dma_dac.count, 
@@ -2418,6 +2429,12 @@
 				if (!ret) ret = -ERESTARTSYS;
 				goto return_free;
 			}
+			down(&s->sem);
+			if (s->dma_dac.mapped)
+			{
+				ret = -ENXIO;
+				goto return_free;
+			}
 			continue;
 		}
 		if (copy_from_user(s->dma_dac.rawbuf + swptr, buffer, cnt)) {
@@ -2439,6 +2456,7 @@
 		start_dac(s);
 	}
 return_free:
+	up(&s->sem);
 	return ret;
 }
 
@@ -2493,11 +2511,12 @@
 
 	VALIDATE_STATE(s);
 	lock_kernel();
+	down(&s->sem);
 	if (vma->vm_flags & VM_WRITE) {
 		if ((ret = prog_dmabuf(s, 1)) != 0)
 			goto out;
 		db = &s->dma_dac;
-	} else 
+	} else { 
 #if 0
 	/* if we can have the wp/wc do the combining
 		we can turn this back on.  */
@@ -2507,19 +2526,23 @@
 		db = &s->dma_adc;
 	} else  
 #endif
+		ret = -EINVAL;
 		goto out;
-	ret = -EINVAL;
+	}
 	if (vma->vm_pgoff != 0)
 		goto out;
 	size = vma->vm_end - vma->vm_start;
 	if (size > (PAGE_SIZE << db->buforder))
+	{
+		ret = -EAGAIN;
 		goto out;
-	ret = -EAGAIN;
+	}
 	if (remap_page_range(vma->vm_start, virt_to_phys(db->rawbuf), size, vma->vm_page_prot))
 		goto out;
 	db->mapped = 1;
 	ret = 0;
 out:
+	up(&s->sem);
 	unlock_kernel();
 	return ret;
 }
@@ -3463,6 +3486,7 @@
 		init_waitqueue_head(&s->open_wait);
 		spin_lock_init(&s->lock);
 		init_MUTEX(&s->open_sem);
+		init_MUTEX(&s->sem);
 		s->magic = ESS_STATE_MAGIC;
 		
 		s->apu[0] = 6*i;