USB audio.c: make trigger semantics more OSS compliant

This patch should make USB audio trigger semantics more OSS compliant.
It is against Redhat's current 2.4 kernel, but should apply also to
other kernels as USB audio.c didn't change a lot the last year or so.

Tom

--- audio.c.original	2003-06-30 16:45:59.000000000 +0200
+++ audio.c	2003-06-30 17:08:26.000000000 +0200
@@ -105,6 +105,8 @@
  *              functionality. Tested and used in production with the emagic emi 2|6 
  *              on PPC and Intel. Also fixed a few logic 'crash and burn' corner 
  *              cases.
+ * 2003-06-30:  Thomas Sailer
+ *              Fix SETTRIGGER non OSS API conformity
  */
 
 /*
@@ -279,23 +281,24 @@
 	unsigned int srate;
 	/* physical buffer */
 	unsigned char *sgbuf[NRSGBUF];
-	unsigned bufsize;
-	unsigned numfrag;
-	unsigned fragshift;
-	unsigned wrptr, rdptr;
-	unsigned total_bytes;
+	unsigned int bufsize;
+	unsigned int numfrag;
+	unsigned int fragshift;
+	unsigned int wrptr, rdptr;
+	unsigned int total_bytes;
 	int count;
-	unsigned error; /* over/underrun */
+	unsigned int error; /* over/underrun */
 	wait_queue_head_t wait;
 	/* redundant, but makes calculations easier */
-	unsigned fragsize;
-	unsigned dmasize;
+	unsigned int fragsize;
+	unsigned int dmasize;
 	/* OSS stuff */
-	unsigned mapped:1;
-	unsigned ready:1;
-	unsigned ossfragshift;
+	unsigned int mapped:1;
+	unsigned int ready:1;
+	unsigned int enabled:1;
+	unsigned int ossfragshift;
 	int ossmaxfrags;
-	unsigned subdivision;
+	unsigned int subdivision;
 };
 
 struct usb_audio_state;
@@ -562,6 +565,7 @@
 			break;
 	}
 	db->bufsize = nr << PAGE_SHIFT;
+	db->enabled = 1;
 	db->ready = 1;
 	dprintk((KERN_DEBUG "usbaudio: dmabuf_init bytepersec %d bufs %d ossfragshift %d ossmaxfrags %d "
 	         "fragshift %d fragsize %d numfrag %d dmasize %d bufsize %d fmt 0x%x srate %d\n",
@@ -2299,7 +2303,7 @@
 		if (cnt > count)
 			cnt = count;
 		if (cnt <= 0) {
-			if (usbin_start(as)) {
+			if (as->usbin.dma.enabled && usbin_start(as)) {
 				if (!ret)
 					ret = -ENODEV;
 				break;
@@ -2332,6 +2336,11 @@
 		count -= cnt;
 		buffer += cnt;
 		ret += cnt;
+		if (as->usbin.dma.enabled && usbin_start(as)) {
+			if (!ret)
+				ret = -ENODEV;
+			break;
+		}
 	}
 	__set_current_state(TASK_RUNNING);
 	remove_wait_queue(&as->usbin.dma.wait, &wait);
@@ -2378,7 +2387,7 @@
 		if (cnt > count)
 			cnt = count;
 		if (cnt <= 0) {
-			if (usbout_start(as)) {
+			if (as->usbout.dma.enabled && usbout_start(as)) {
 				if (!ret)
 					ret = -ENODEV;
 				break;
@@ -2411,7 +2420,7 @@
 		count -= cnt;
 		buffer += cnt;
 		ret += cnt;
-		if (as->usbout.dma.count >= start_thr && usbout_start(as)) {
+		if (as->usbout.dma.enabled && as->usbout.dma.count >= start_thr && usbout_start(as)) {
 			if (!ret)
 				ret = -ENODEV;
 			break;
@@ -2616,19 +2625,25 @@
 			if (val & PCM_ENABLE_INPUT) {
 				if (!as->usbin.dma.ready && (ret = prog_dmabuf_in(as)))
 					return ret;
+				as->usbin.dma.enabled = 1;
 				if (usbin_start(as))
 					return -ENODEV;
-			} else
+			} else {
+				as->usbin.dma.enabled = 0;
 				usbin_stop(as);
+			}
 		}
 		if (file->f_mode & FMODE_WRITE) {
 			if (val & PCM_ENABLE_OUTPUT) {
 				if (!as->usbout.dma.ready && (ret = prog_dmabuf_out(as)))
 					return ret;
+				as->usbout.dma.enabled = 1;
 				if (usbout_start(as))
 					return -ENODEV;
-			} else
+			} else {
+				as->usbout.dma.enabled = 0;
 				usbout_stop(as);
+			}
 		}
 		return 0;
 
@@ -2827,10 +2842,14 @@
 		if (signal_pending(current))
 			return -ERESTARTSYS;
 	}
-	if (file->f_mode & FMODE_READ)
+	if (file->f_mode & FMODE_READ) {
 		as->usbin.dma.ossfragshift = as->usbin.dma.ossmaxfrags = as->usbin.dma.subdivision = 0;
-	if (file->f_mode & FMODE_WRITE)
+		as->usbin.dma.enabled = 1;
+	}
+	if (file->f_mode & FMODE_WRITE) {
 		as->usbout.dma.ossfragshift = as->usbout.dma.ossmaxfrags = as->usbout.dma.subdivision = 0;
+		as->usbout.dma.enabled = 1;
+	}
 	if (set_format(as, file->f_mode, ((minor & 0xf) == SND_DEV_DSP16) ? AFMT_S16_LE : AFMT_U8 /* AFMT_ULAW */, 8000)) {
 		up(&open_sem);
 		return -EIO;