The latency timer was introduced with the FT232BM and FT245BM chips. Do not bother attempting to read or write it for older chip versions. Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx> --- v2: - No change. --- drivers/usb/serial/ftdi_sio.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index c540de15aad2..72314734dfd0 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -1406,6 +1406,9 @@ static int write_latency_timer(struct usb_serial_port *port) int rv; int l = priv->latency; + if (priv->chip_type == SIO || priv->chip_type == FT8U232AM) + return -EINVAL; + if (priv->flags & ASYNC_LOW_LATENCY) l = 1; @@ -1429,6 +1432,9 @@ static int read_latency_timer(struct usb_serial_port *port) unsigned char *buf; int rv; + if (priv->chip_type == SIO || priv->chip_type == FT8U232AM) + return -EINVAL; + buf = kmalloc(1, GFP_KERNEL); if (!buf) return -ENOMEM; -- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
