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Mon, 28 Nov 2022 18:12:57 +0000 From: Alex Henrie To: linux-usb@vger.kernel.org, johan@kernel.org, gregkh@linuxfoundation.org, s.shtylyov@omp.ru, alexhenrie24@gmail.com Cc: Alex Henrie Subject: [PATCH v2] USB: serial: cp210x: map B0 to B9600 Date: Mon, 28 Nov 2022 11:12:22 -0700 Message-Id: <20221128181222.182554-1-alexh@vpitech.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221126035825.6991-1-alexh@vpitech.com> References: <20221126035825.6991-1-alexh@vpitech.com> X-ClientProxiedBy: CY5PR19CA0084.namprd19.prod.outlook.com (2603:10b6:930:69::20) To SA1P222MB0296.NAMP222.PROD.OUTLOOK.COM (2603:10b6:806:1ff::7) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: SA1P222MB0296:EE_|PH0P222MB0111:EE_ X-MS-Office365-Filtering-Correlation-Id: d3910d28-8606-4495-b9f9-08dad16c2d59 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255; 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Some old versions of the NXP blhost utility depend on this behavior. However, the CP210x driver resets the baud rate to the minimum supported rate of 300. Special-case B0 so that it returns the baud rate to the more sensible default of 9600. Signed-off-by: Alex Henrie --- drivers/usb/serial/cp210x.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index 3bcec419f463..b2409167b27f 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -1051,9 +1051,13 @@ static void cp210x_change_speed(struct tty_struct *tty, * This maps the requested rate to the actual rate, a valid rate on * cp2102 or cp2103, or to an arbitrary rate in [1M, max_speed]. * - * NOTE: B0 is not implemented. + * NOTE: B0 is not implemented, apart from returning the baud rate to + * the default of B9600. */ - baud = clamp(tty->termios.c_ospeed, priv->min_speed, priv->max_speed); + if (tty->termios.c_ospeed) + baud = clamp(tty->termios.c_ospeed, priv->min_speed, priv->max_speed); + else + baud = 9600; if (priv->use_actual_rate) baud = cp210x_get_actual_rate(baud); @@ -1069,7 +1073,8 @@ static void cp210x_change_speed(struct tty_struct *tty, baud = 9600; } - tty_encode_baud_rate(tty, baud, baud); + if (tty->termios.c_ospeed) + tty_encode_baud_rate(tty, baud, baud); } static void cp210x_enable_event_mode(struct usb_serial_port *port)