[PATCH] Re: 2.6.3-bk9 QA testing: firewire good, USB printing dead

[Barry K. Nathan]

Does this patch (following my signature) fix the printer hangs?
(It does for me.)

BTW, it's also an attachment on OSDL bugzilla #2221:
http://bugme.osdl.org/show_bug.cgi?id=2221

-Barry K. Nathan <barryn@xxxxxxxxx>

diff -ruN linux-2.6.3-bk2/drivers/usb/class/usblp.c linux-2.6.3-bk2-bkn1/drivers/usb/class/usblp.c
--- linux-2.6.3-bk2/drivers/usb/class/usblp.c	2004-02-29 23:18:26.000000000 -0800
+++ linux-2.6.3-bk2-bkn1/drivers/usb/class/usblp.c	2004-02-29 23:17:24.000000000 -0800
@@ -603,7 +603,7 @@
 {
 	DECLARE_WAITQUEUE(wait, current);
 	struct usblp *usblp = file->private_data;
-	int timeout, err = 0, transfer_length;
+	int timeout, err = 0, transfer_length = 0;
 	size_t writecount = 0;
 
 	while (writecount < count) {
@@ -654,6 +654,16 @@
 			continue;
 		}
 
+		/* We must increment writecount here, and not at the
+		 * end of the loop. Otherwise, the final loop iteration may
+		 * be skipped, leading to incomplete printer output.
+		 */
+		writecount += transfer_length;
+		if (writecount == count) {
+			up (&usblp->sem);
+			break;
+		}
+
 		transfer_length=(count - writecount);
 		if (transfer_length > USBLP_BUF_SIZE)
 			transfer_length = USBLP_BUF_SIZE;
@@ -677,8 +687,6 @@
 			break;
 		}
 		up (&usblp->sem);
-
-		writecount += transfer_length;
 	}
 
 	return count;
-
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