USB: re-enable interface after driver unbinds
This patch (as1197) fixes an error introduced recently. Since a
significant number of devices can't handle Set-Interface requests, we
no longer call usb_set_interface() when a driver unbinds from an
interface, provided the interface is already in altsetting 0. However
the interface still does get disabled, and the call to
usb_set_interface() was the only thing re-enabling it. Since the
interface doesn't get re-enabled, further attempts to use it fail.
So the patch adds a call to usb_enable_interface() when a driver
unbinds and the interface is in altsetting 0. For this to work
right, the interface's endpoints have to be re-enabled but their
toggles have to be left alone. Therefore an additional argument is
added to usb_enable_endpoint() and usb_enable_interface(), a flag
indicating whether or not the endpoint toggles should be reset.
This is a forward-ported version of a patch which fixes Bugzilla
#12301.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: David Roka <roka@dawid.hu>
Reported-by: Erik Ekman <erik@kryo.se>
Tested-by: Erik Ekman <erik@kryo.se>
Tested-by: Alon Bar-Lev <alon.barlev@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 41c0602..9876055 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -295,9 +295,12 @@
* altsetting means creating new endpoint device entries).
* When either of these happens, defer the Set-Interface.
*/
- if (intf->cur_altsetting->desc.bAlternateSetting == 0)
- ; /* Already in altsetting 0 so skip Set-Interface */
- else if (!error && intf->dev.power.status == DPM_ON)
+ if (intf->cur_altsetting->desc.bAlternateSetting == 0) {
+ /* Already in altsetting 0 so skip Set-Interface.
+ * Just re-enable it without affecting the endpoint toggles.
+ */
+ usb_enable_interface(udev, intf, false);
+ } else if (!error && intf->dev.power.status == DPM_ON)
usb_set_interface(udev, intf->altsetting[0].
desc.bInterfaceNumber, 0);
else