ulpt_tick after close

[Ian Dowse]

In message <42998B18.8020806 at radiotube.org>, Jan-Espen Pettersen writes:
>I think I'll replace that printf with a panic in ulpt_read_cb to get a 
>backtrace next time. (And at the same time update my sources) As it 
>would reveal what is actually calling ulpt_read_cb after the callout has 
>been stopped. The problem is that this is very unlikely to happen during 
>a single print job, but it does over time, so it might take me some time 
>to get that backtrace.

Thanks for the details. By the way, is it lpd or something else
that is actually accessing the ulpt device? Below is a patch you
could try that will hopefully find out a bit more about what is
going on. You could also change the new return statement in
ulpt_read_cb() to a panic, as the stack trace might reveal more
information like you say.

Ian

Index: ulpt.c
===================================================================
RCS file: /dump/FreeBSD-CVS/src/sys/dev/usb/ulpt.c,v
retrieving revision 1.65.2.1
diff -u -r1.65.2.1 ulpt.c
--- ulpt.c	30 Jan 2005 01:00:10 -0000	1.65.2.1
+++ ulpt.c	29 May 2005 11:51:30 -0000
@@ -122,6 +122,7 @@
 #define	ULPT_OPEN	0x01	/* device is open */
 #define	ULPT_OBUSY	0x02	/* printer is busy doing output */
 #define	ULPT_INIT	0x04	/* waiting to initialize for open */
+#define	ULPT_CLOSING	0x05	/* closing */
 	u_char sc_flags;
 #define	ULPT_NOPRIME	0x40	/* don't prime on open */
 	u_char sc_laststatus;
@@ -660,9 +661,13 @@
 
 	USB_GET_SC(ulpt, ULPTUNIT(dev), sc);
 
-	if (sc->sc_state != ULPT_OPEN)
+	if (sc->sc_state != ULPT_OPEN) {
 		/* We are being forced to close before the open completed. */
+		printf("%s: ignoring close in state %d\n", 
+		    USBDEVNAME(sc->sc_dev), sc->sc_state);
 		return (0);
+	}
+	sc->sc_state = ULPT_CLOSING;
 
 	if (sc->sc_has_callout) {
 		usb_uncallout(sc->sc_read_callout, ulpt_tick, sc);
@@ -810,6 +815,13 @@
 	usbd_get_xfer_status(xfer, &xsc, NULL, &n, &err);
 	sc = xsc;
 
+	if (sc->sc_state != ULPT_OPEN && (status != USBD_CANCELLED ||
+	    err != USBD_CANCELLED)) {
+		printf("%s: ulpt_read_cb state=%d status=%s err=%s\n",
+		    USBDEVNAME(sc->sc_dev), sc->sc_state, usbd_errstr(status),
+		    usbd_errstr(err));
+		return;
+	}
 	DPRINTFN(1,("ulpt_read_cb: start sc=%p, err=%d n=%d\n", sc, err, n));
 
 #ifdef ULPT_DEBUG
@@ -832,6 +844,11 @@
 
 	DPRINTFN(1,("ulpt_tick: start sc=%p\n", sc));
 
+	if (sc->sc_state != ULPT_OPEN) {
+		printf("%s: ulpt_tick state=%d\n", USBDEVNAME(sc->sc_dev),
+		    sc->sc_state);
+		return;
+	}
 	usbd_setup_xfer(sc->sc_in_xfer, sc->sc_in_pipe, sc, sc->sc_in_buf,
 			ULPT_BSIZE, USBD_NO_COPY | USBD_SHORT_XFER_OK,
 			ULPT_READ_TIMO, ulpt_read_cb);