From: Johan Hovold <johan@kernel.org> commit c01d2c58698f710c9e13ba3e2d296328606f74fd upstream. Make sure to clear the write-busy flag also in case no new data was submitted due to lack of device buffer space so that writing is resumed once space again becomes available. Fixes: 507ca9bc0476 ("[PATCH] USB: add ability for usb-serial drivers to determine if their write urb is currently being used.") Cc: stable <stable@vger.kernel.org> # 2.6.13 Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/usb/serial/keyspan_pda.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/serial/keyspan_pda.c b/drivers/usb/serial/keyspan_pda.c index 88e835ff70fe..de16223bf030 100644 --- a/drivers/usb/serial/keyspan_pda.c +++ b/drivers/usb/serial/keyspan_pda.c @@ -548,7 +548,7 @@ static int keyspan_pda_write(struct tty_struct *tty, rc = count; exit: - if (rc < 0) + if (rc <= 0) set_bit(0, &port->write_urbs_free); return rc; } -- 2.25.1