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 9f52859583cb71e21bf2c8a375336de094755375..5a703c33de1c9a89bc4df5ce5286a4b0a5173634 100644 (file)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -322,17 +322,17 @@ 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);