From f976d0e5747ca65ccd0fb2a4118b193d70aa1836 Mon Sep 17 00:00:00 2001
From: Tobias Herzog <t-herzog@gmx.de>
Date: Sat, 22 Sep 2018 22:11:11 +0200
Subject: [PATCH] cdc-acm: correct counting of UART states in serial state notification
Git-commit: f976d0e5747ca65ccd0fb2a4118b193d70aa1836
Patch-mainline: v4.19
References: bsc#1051510

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>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/usb/class/cdc-acm.c |   14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -322,17 +322,17 @@ static void acm_process_notification(str
 
 		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);