[PATCH] Re: cdc-acm problems

[Colin Leroy <colin _at_ xxxxxxxxxx>]

> I have problems with cdc-acm killing ohci. I tried to narrow down the problem, 
> but didn't get far. 
> Basically `killall -HUP pppd` gives (in dmesg):
> 
> drivers/usb/class/cdc-acm.c: acm_ctrl_irq - urb shutting down with status: -2
> ohci_hcd 0001:01:1b.1: OHCI Unrecoverable Error, disabled
> ohci_hcd 0001:01:1b.1: HC died; cleaning up
> usb 4-1: USB disconnect, address 2
> bus usb: remove device 4-1:1.0
> bus usb: remove device 4-1:1.1
> bus usb: remove device 4-1

After having looked some more hours, it looks like acm_tty_close() unlinks 
urbs too soon or something like that... The attached patch fixes it for me 
(I don't think it's really clean, but it may help ?)

-- 
Colin
Index: drivers/usb/class/cdc-acm.c
===================================================================
RCS file: /home/cvsroot/linuxppc/drivers/usb/class/cdc-acm.c,v
retrieving revision 1.1.1.1
diff -u -u -r1.1.1.1 cdc-acm.c
--- drivers/usb/class/cdc-acm.c	8 Jan 2004 11:25:51 -0000	1.1.1.1
+++ drivers/usb/class/cdc-acm.c	13 Jan 2004 20:40:39 -0000
@@ -157,6 +157,7 @@
 	unsigned int minor;				/* acm minor number */
 	unsigned char throttle;				/* throttled by tty layer */
 	unsigned char clocal;				/* termios CLOCAL */
+	unsigned int finish_remove;			/* finish removing */
 };
 
 static struct usb_driver acm_driver;
@@ -214,8 +215,16 @@
 		goto exit;
 	}
 
-	if (!ACM_READY(acm))
+	if (!ACM_READY(acm)) {
+		if (acm->finish_remove) {
+			dbg("unlinking urbs");
+			usb_unlink_urb(acm->ctrlurb);
+			usb_unlink_urb(acm->writeurb);
+			usb_unlink_urb(acm->readurb);
+			return;			
+		}
 		goto exit;
+	}
 
 	switch (dr->bRequest) {
 
@@ -382,9 +391,7 @@
 	if (!--acm->used) {
 		if (acm->dev) {
 			acm_set_control(acm, acm->ctrlout = 0);
-			usb_unlink_urb(acm->ctrlurb);
-			usb_unlink_urb(acm->writeurb);
-			usb_unlink_urb(acm->readurb);
+			acm->finish_remove = 1;
 		} else {
 			tty_unregister_device(acm_tty_driver, acm->minor);
 			acm_table[acm->minor] = NULL;