spca-20060501-usb-bandwidth-fix.patch

spca-20060501-usb-bandwidth-fix.patch (text/plain), 3.28 KB, created by Conrad Kostecki on 2006-09-26 23:55:37 UTC

diff -urN spca5xx-20060501.orig/drivers/usb/spca5xx.c spca5xx-20060501/drivers/usb/spca5xx.c
--- spca5xx-20060501.orig/drivers/usb/spca5xx.c	2006-04-29 11:38:07.000000000 -0400
+++ spca5xx-20060501/drivers/usb/spca5xx.c	2006-09-05 13:19:04.000000000 -0400
@@ -1574,6 +1574,66 @@
       spca50x->funct.stopN(spca50x);
 }
 
+
+/**********************************************************************
+* spcaReducePacketSize
+* Function Fixes the bandwidth problem that occurs
+* when other USB devices are on the same host controller bus as the
+* camera by gradually lowering the bandwidth requirements of the driver.
+* It works even when other USB devices are present on the same
+* host controller bus as the camera. 
+*
+* Problem
+* When other USB devices are present on the same host controller
+* bus as the camera, the bandwidth requirements of the spca5xx driver
+* are not being met. The spca5xx driver is asking for more bandwidth
+* than is available which results in the following error messages:
+*
+* No space left on device
+* can't open /dev/video0: No space left on device.
+* usb_submit_urb(0) ret -28
+*
+* 
+* Many thanks to all the wonderful people contributing to this project.
+*
+* Great work!
+* vodunvibe [AT] [e-mail] yahoo DOT com
+* 2006-08-27
+* 
+***********************************************************************/
+static int spcaReducePacketSize(struct usb_spca50x *spca50x, int n, int err)
+{
+    int size=896, fx, i;
+    err("spcaReducePacketSize: vodunvibe - The usb_submit_urb(%d) transfer request submission failed - You probably have another device sharing the same USB Host Controller Bus as your camera. Try using another USB port, on a different host controller bus.", n);
+    while (err == -ENOSPC && size >= 0) {
+	    err("spcaReducePacketSize: vodunvibe - Lowering the bandwidth requirements - New packet size (%d) ", size);
+        spca50x_set_packet_size(spca50x, size);
+    	spca50x->sbuf[n].urb->transfer_buffer_length = spca50x->packet_size * FRAMES_PER_DESC;
+    	for (fx = 0; fx < FRAMES_PER_DESC; fx++) {
+    	    spca50x->sbuf[n].urb->iso_frame_desc[fx].offset = spca50x->packet_size * fx;
+    	    spca50x->sbuf[n].urb->iso_frame_desc[fx].length = spca50x->packet_size;
+    	}
+        size-=128;
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,5,41)
+    	err = usb_submit_urb(spca50x->sbuf[n].urb, GFP_KERNEL);
+#else
+    	err = usb_submit_urb(spca50x->sbuf[n].urb);
+#endif
+    }
+
+	if (!err) {
+      for (i = 0; i < SPCA50X_NUMSBUF; i++) {
+    	spca50x->sbuf[i].urb->transfer_buffer_length = spca50x->packet_size * FRAMES_PER_DESC;
+    	for (fx = 0; fx < FRAMES_PER_DESC; fx++) {
+    	    spca50x->sbuf[i].urb->iso_frame_desc[fx].offset = spca50x->packet_size * fx;
+    	    spca50x->sbuf[i].urb->iso_frame_desc[fx].length = spca50x->packet_size;
+    	}
+      }
+    }
+    return err;
+}
+
+
 static int spca50x_init_isoc(struct usb_spca50x *spca50x)
 {
 
@@ -1649,7 +1709,15 @@
 #endif
 	if (err) {
 	    err("init isoc: usb_submit_urb(%d) ret %d", n, err);
-	    return err;
+	    if (err == -ENOSPC) {
+	        err = spcaReducePacketSize(spca50x, n, err);
+        	if (err) {
+	            err("init isoc: After spcaReducePacketSize - usb_submit_urb(%d) ret %d", n, err);
+         	    return err;
+        	}
+	    }else{
+	        return err;
+	    }
 	}
     }