PERFORCE change 144450 for review

[Hans Petter Selasky]

http://perforce.freebsd.org/chv.cgi?CH=144450

Change 144450 by hselasky at hselasky_laptop001 on 2008/07/01 23:36:42

	
	Workaround panic at USB sound device detach during
	playback! There might be a deadlock situation here
	if the USB sound device is located on the same HUB
	like the mouse and keyboard, and the HUB is detached,
	but else this works fine and is better than nothing.

Affected files ...

.. //depot/projects/usb/src/sys/dev/usb2/sound/uaudio2.c#3 edit

Differences ...

==== //depot/projects/usb/src/sys/dev/usb2/sound/uaudio2.c#3 (text+ko) ====

@@ -661,11 +661,6 @@
 		device_printf(dev, "No midi sequencer\n");
 	}
 
-	if (sc->sc_play_chan.valid ||
-	    sc->sc_rec_chan.valid) {
-		device_printf(dev, "WARNING: Unplugging the device while "
-		    "it is in use will cause a panic!\n");
-	}
 	DPRINTF(0, "doing child attach\n");
 
 	/* attach the children */
@@ -760,6 +755,7 @@
 	struct uaudio_softc *sc = device_get_softc(device_get_parent(dev));
 	int error = 0;
 
+repeat:
 	if (sc->sc_pcm_registered) {
 		error = pcm_unregister(dev);
 	} else {
@@ -769,8 +765,11 @@
 	}
 
 	if (error) {
-		panic("Please don't detach your sound device "
-		    "while it is in use. This is not supported yet!\n");
+		device_printf(dev, "Waiting for sound application to exit!\n");
+		mtx_lock(&Giant);
+		usb2_pause_mtx(&Giant, 2000);
+		mtx_unlock(&Giant);
+		goto repeat;		/* try again */
 	}
 	return (0);			/* success */
 }