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 25ae9b9895a97b7696fcf568c0c34deeda4f2056..dbe44e890c99c994fab9d5d8191f766067319137 100644 (file)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -333,17 +333,17 @@ static void acm_ctrl_irq(struct urb *urb)
 
                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);