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| author | Johan Hovold <johan@kernel.org> | 2017-01-06 19:15:17 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-05-14 14:08:26 +0200 |
| commit | 1077176a2456691525a02a666e9d1d24447341f7 (patch) | |
| tree | 4d9263a1d8f5b93cc624e855db40249fb75871f9 | |
| parent | e40bbb3970749d490af2c2d52de496e85f810ea1 (diff) | |
| download | linux-stable-1077176a2456691525a02a666e9d1d24447341f7.tar.gz linux-stable-1077176a2456691525a02a666e9d1d24447341f7.tar.bz2 linux-stable-1077176a2456691525a02a666e9d1d24447341f7.zip | |
USB: serial: ch341: fix modem-status handling
commit a0467a967f347842b30739aae636c44980265265 upstream.
The modem-status register was read as part of device configuration at
port_probe and then again at open (and reset-resume). During open (and
reset-resume) the MSR was read before submitting the interrupt URB,
something which could lead to an MSR-change going unnoticed when it
races with open (reset-resume).
Fix this by dropping the redundant reconfiguration of the port at every
open, and only read the MSR after the interrupt URB has been submitted.
Fixes: 664d5df92e88 ("USB: usb-serial ch341: support for DTR/RTS/CTS")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/serial/ch341.c | 27 |
1 files changed, 12 insertions, 15 deletions
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c index 95aa5233726c..86692d2f8523 100644 --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -248,21 +248,11 @@ static int ch341_configure(struct usb_device *dev, struct ch341_private *priv) if (r < 0) goto out; - /* expect 0xff 0xee */ - r = ch341_get_status(dev, priv); - if (r < 0) - goto out; - r = ch341_set_baudrate_lcr(dev, priv, priv->lcr); if (r < 0) goto out; r = ch341_set_handshake(dev, priv->line_control); - if (r < 0) - goto out; - - /* expect 0x9f 0xee */ - r = ch341_get_status(dev, priv); out: kfree(buffer); return r; @@ -334,14 +324,9 @@ static void ch341_close(struct usb_serial_port *port) /* open this device, set default parameters */ static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) { - struct usb_serial *serial = port->serial; struct ch341_private *priv = usb_get_serial_port_data(port); int r; - r = ch341_configure(serial->dev, priv); - if (r) - return r; - if (tty) ch341_set_termios(tty, port, NULL); @@ -353,6 +338,12 @@ static int ch341_open(struct tty_struct *tty, struct usb_serial_port *port) return r; } + r = ch341_get_status(port->serial->dev, priv); + if (r < 0) { + dev_err(&port->dev, "failed to read modem status: %d\n", r); + goto err_kill_interrupt_urb; + } + r = usb_serial_generic_open(tty, port); if (r) goto err_kill_interrupt_urb; @@ -619,6 +610,12 @@ static int ch341_reset_resume(struct usb_serial *serial) ret); return ret; } + + ret = ch341_get_status(port->serial->dev, priv); + if (ret < 0) { + dev_err(&port->dev, "failed to read modem status: %d\n", + ret); + } } return usb_serial_generic_resume(serial); |