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Commit 2dea7cd7 authored by Ian Abbott's avatar Ian Abbott Committed by Johan Hovold
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USB: serial: ftdi_sio: don't access latency timer on old chips 



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: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarJohan Hovold <johan@kernel.org>
parent 4495c08e

drivers/usb/serial/ftdi_sio.c

+6 −0
Original line number Diff line number Diff line
@@ -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;