| Message ID | 20210118111331.5048-3-johan@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | None | expand |
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index 5bd14770065b..ee0139eb6636 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -1181,6 +1181,9 @@ static void cp210x_set_flow_control(struct tty_struct *tty, else flow_repl &= ~CP210X_SERIAL_AUTO_TRANSMIT; + flow_ctl.ulXonLimit = cpu_to_le32(128); + flow_ctl.ulXoffLimit = cpu_to_le32(128); + dev_dbg(&port->dev, "%s - ulControlHandshake=0x%08x, ulFlowReplace=0x%08x\n", __func__, ctl_hs, flow_repl);
At least CP2102 requires the XON/XOFF limits to be initialised in order for software input flow control (IXOFF) to work. Specifically, XOFF is never sent if the XOFF limit is left at its default value of zero. Set the limits so that input is throttled when the FIFO free level drops below 128 bytes and restarted when the FIFO fill level drops below 128 bytes. Note that the threshold values have been chosen so that they can be used also with CP2105 which has the smallest FIFO of the currently supported device types (288 byte for the SCI port). If needed the limits can be made device specific later. Signed-off-by: Johan Hovold <johan@kernel.org> --- drivers/usb/serial/cp210x.c | 3 +++ 1 file changed, 3 insertions(+)