| Message ID | 20210412093815.736-4-johan@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | c505b8b2ef274ce60a79f18a33bf23efd17a04de |
| Headers | show |
| Series | USB: serial: closing-wait fixes and cleanups | expand |
diff --git a/drivers/usb/serial/ti_usb_3410_5052.c b/drivers/usb/serial/ti_usb_3410_5052.c index 03839289d6c0..8ed64115987f 100644 --- a/drivers/usb/serial/ti_usb_3410_5052.c +++ b/drivers/usb/serial/ti_usb_3410_5052.c @@ -610,7 +610,11 @@ static int ti_port_probe(struct usb_serial_port *port) usb_set_serial_port_data(port, tport); - port->port.drain_delay = 3; + /* + * The TUSB5052 LSR does not tell when the transmitter shift register + * has emptied so add a one-character drain delay. + */ + port->port.drain_delay = 1; return 0; }
The three-character drain delay was added by commit f1175daa5312 ("USB: ti_usb_3410_5052: kill custom closing_wait") when removing the custom closing-wait implementation, which used a fixed 20 ms poll period and drain delay. This was likely a bit too conservative as a one-character timeout (e.g. 33 ms at 300 bps) should be enough to compensate for the lack of a transmitter empty bit in the TUSB5052 line-status register. Signed-off-by: Johan Hovold <johan@kernel.org> --- drivers/usb/serial/ti_usb_3410_5052.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)