Re: USB broken in 2.4.4? Serial Ricochet works, USB performance sucks.

[Greg KH <greg@kroah.com>]

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On Thu, May 10, 2001 at 08:07:50PM -0700, Drew Bertola wrote:
> 
> Joey Hess had a problem similar to what you described, though he noticed
> it while using the pcmcia ricochet modem.  He passed along this patch:

Doh!  I've only fixed this same kind of problem about 3 different times
in the usb-serial drivers.  clameter, could you try the attached patch
against 2.4.4 and see if that fixes the MTU issue for you?

Thanks Drew for reminding me of this.

greg k-h


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--- linux-2.4.4/drivers/usb/acm.c	Fri Feb 16 16:06:17 2001
+++ linux-2.4/drivers/usb/acm.c	Thu May 10 21:29:29 2001
@@ -233,8 +240,14 @@
 		dbg("nonzero read bulk status received: %d", urb->status);
 
 	if (!urb->status & !acm->throttle)  {
-		for (i = 0; i < urb->actual_length && !acm->throttle; i++)
+		for (i = 0; i < urb->actual_length && !acm->throttle; i++) {
+			/* if we insert more than TTY_FLIPBUF_SIZE characters, 
+			 * we drop them. */
+			if (tty->flip.count >= TTY_FLIPBUF_SIZE) {
+				tty_flip_buffer_push(tty);
+			}
 			tty_insert_flip_char(tty, data[i], 0);
+		}
 		tty_flip_buffer_push(tty);
 	}