| Message ID | 9E531B87-06A8-45F0-A2A8-EC6FA61A99A7@silabs.com |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] USB: serial: cp210x: Fix error 32 when hardware flow control is enabled. | expand |
On Thu, Jan 21, 2021 at 07:09:13AM +0000, Pho Tran wrote: > Fix error 32 returned by CP210X_SET_MHS when hardware flow control is enabled. > > The root cause of error 32 is that user application (CoolTerm, linux-serial-test) > opened cp210x device with hardware flow control then attempt to control RTS/DTR pins. > In hardware flow control, RTS/DTR pins will be controlled by hardware only, > any attempt to control those pins will cause error 32 from the device. > This fix will block MHS command(command to control RTS/DTR pins) to the device > if hardware flow control is being used. > > Signed-off-by: Pho Tran <pho.tran@silabs.com> > --- > 01/19/2021: Patch v2 Modified based on comment from Johan Hovold <johan@kernel.org> > and Greg Kroah-Hartman <gregkh@linuxfoundation.org> > --- > drivers/usb/serial/cp210x.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c > index fbb10dfc56e3..5b6bbda2b424 100644 > --- a/drivers/usb/serial/cp210x.c > +++ b/drivers/usb/serial/cp210x.c > @@ -1204,7 +1204,12 @@ static int cp210x_tiocmset(struct tty_struct *tty, > unsigned int set, unsigned int clear) > { > struct usb_serial_port *port = tty->driver_data; > - return cp210x_tiocmset_port(port, set, clear); > + if (C_CRTSCTS(tty)) > + > + /* Don't send SET_MHS command if device in hardware flow control mode. */ > + return 0; That indentation and whitespace is very odd. Did you run checkpatch.pl on your change before sending it to us to verify that all is ok? Please do so. thanks, greg k-h
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index fbb10dfc56e3..5b6bbda2b424 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -1204,7 +1204,12 @@ static int cp210x_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear) { struct usb_serial_port *port = tty->driver_data; - return cp210x_tiocmset_port(port, set, clear); + if (C_CRTSCTS(tty)) + + /* Don't send SET_MHS command if device in hardware flow control mode. */ + return 0; + else + return cp210x_tiocmset_port(port, set, clear); } static int cp210x_tiocmset_port(struct usb_serial_port *port,
Fix error 32 returned by CP210X_SET_MHS when hardware flow control is enabled. The root cause of error 32 is that user application (CoolTerm, linux-serial-test) opened cp210x device with hardware flow control then attempt to control RTS/DTR pins. In hardware flow control, RTS/DTR pins will be controlled by hardware only, any attempt to control those pins will cause error 32 from the device. This fix will block MHS command(command to control RTS/DTR pins) to the device if hardware flow control is being used. Signed-off-by: Pho Tran <pho.tran@silabs.com> --- 01/19/2021: Patch v2 Modified based on comment from Johan Hovold <johan@kernel.org> and Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/usb/serial/cp210x.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)