cdc-acm: correct counting of UART states in serial state notification

commit f976d0e5747ca65ccd0fb2a4118b193d70aa1836 upstream.

The usb standard ("Universal Serial Bus Class Definitions for Communication
Devices") distiguishes between "consistent signals" (DSR, DCD), and
"irregular signals" (break, ring, parity error, framing error, overrun).
The bits of "irregular signals" are set, if this error/event occurred on
the device side and are immeadeatly unset, if the serial state notification
was sent.
Like other drivers of real serial ports do, just the occurence of those
events should be counted in serial_icounter_struct (but no 1->0
transitions).

Signed-off-by: Tobias Herzog <t-herzog@gmx.de>
Acked-by: Oliver Neukum <oneukum@suse.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 64fdd67448d72d3e89cc3eed94f8b268106b60e2..539a8a8f028ed3657b0c9286b9c1ed714ab48525 100644 (file)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -309,17 +309,17 @@ static void acm_process_notification(struct acm *acm, unsigned char *buf)
 
                if (difference & ACM_CTRL_DSR)
                        acm->iocount.dsr++;
-               if (difference & ACM_CTRL_BRK)
-                       acm->iocount.brk++;
-               if (difference & ACM_CTRL_RI)
-                       acm->iocount.rng++;
                if (difference & ACM_CTRL_DCD)
                        acm->iocount.dcd++;
-               if (difference & ACM_CTRL_FRAMING)
+               if (newctrl & ACM_CTRL_BRK)
+                       acm->iocount.brk++;
+               if (newctrl & ACM_CTRL_RI)
+                       acm->iocount.rng++;
+               if (newctrl & ACM_CTRL_FRAMING)
                        acm->iocount.frame++;
-               if (difference & ACM_CTRL_PARITY)
+               if (newctrl & ACM_CTRL_PARITY)
                        acm->iocount.parity++;
-               if (difference & ACM_CTRL_OVERRUN)
+               if (newctrl & ACM_CTRL_OVERRUN)
                        acm->iocount.overrun++;
                spin_unlock(&acm->read_lock);