From: Johan Hovold johan@kernel.org
commit 696c541c8c6cfa05d65aa24ae2b9e720fc01766e upstream.
Commit c528fcb116e6 ("USB: serial: keyspan_pda: fix receive sanity checks") broke write-unthrottle handling by dropping well-formed unthrottle-interrupt packets which are precisely two bytes long. This could lead to blocked writers not being woken up when buffer space again becomes available.
Instead, stop unconditionally printing the third byte which is (presumably) only valid on modem-line changes.
Fixes: c528fcb116e6 ("USB: serial: keyspan_pda: fix receive sanity checks") Cc: stable stable@vger.kernel.org # 4.11 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 | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/usb/serial/keyspan_pda.c +++ b/drivers/usb/serial/keyspan_pda.c @@ -176,11 +176,11 @@ static void keyspan_pda_rx_interrupt(str break; case 1: /* status interrupt */ - if (len < 3) { + if (len < 2) { dev_warn(&port->dev, "short interrupt message received\n"); break; } - dev_dbg(&port->dev, "rx int, d1=%d, d2=%d\n", data[1], data[2]); + dev_dbg(&port->dev, "rx int, d1=%d\n", data[1]); switch (data[1]) { case 1: /* modemline change */ break;