This fixes a deadlock appearing with some USB peripheral drivers
when running CDC ACM gadget code.
The newish (2.6.27) CDC ACM event notification mechanism sends
messages (IN to the host) which are short enough to fit in most
FIFOs. That means that with some peripheral controller drivers
(evidently not the ones used to verify the notification code!!)
the completion callback can be issued before queue() returns.
The deadlock would come because the completion callback and the
event-issuing code shared a spinlock. Fix is trivial: drop
that lock while queueing the message.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Update the CDC-ACM gadget code to support the peripheral-to-host
notifications when the tty is opened or closed, or issues a BREAK.
The serial framework code calls new generic hooks; right now only
CDC-ACM uses those hooks. This resolves several REVISIT comments
in the code. (Based on a patch from Felipe Balbi.)
Note that this doesn't expose USB_CDC_CAP_BRK to the host, since
this code still rejects USB_CDC_REQ_SEND_BREAK control requests
for host-to-peripheral BREAK signaling (received via /dev/ttyGS*).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This removes some unused members from the various USB functions.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Split out CDC ACM parts of "gadget serial" to a "function driver".
Some key structural differences from the previous ACM support, shared
with with the generic serial function (next patch):
- As a function driver, it can be combined with other functions.
One gadget configuration could offer both serial and network
links, as an example.
- One serial port can be exposed in multiple configurations;
the /dev/ttyGS0 node could be exposed regardless of which
config the host selected.
- One configuration can expose multiple serial ports, such as
ttyGS0, ttyGS1, ttyGS2, and ttyGS3.
This code should be a lot easier to understand than the previous
all-in-one-big-file version of the driver.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
David Brownell