Re: [PATCH v3] USB: serial: cp210x: Fix error 32 when hardware flow control is enabled.
On Thu, Jan 21, 2021 at 07:09:13AM +, 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
> ---
> 01/19/2021: Patch v2 Modified based on comment from Johan Hovold
>
> and Greg Kroah-Hartman
> ---
> 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
[PATCH v3] USB: serial: cp210x: Fix error 32 when hardware flow control is enabled.
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
---
01/19/2021: Patch v2 Modified based on comment from Johan Hovold
and Greg Kroah-Hartman
---
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;
+ else
+ return cp210x_tiocmset_port(port, set, clear);
}
static int cp210x_tiocmset_port(struct usb_serial_port *port,
--
2.17.1
