From bf5e5834bffc62b50cd4a201804506eb11ef1af8 Mon Sep 17 00:00:00 2001 From: Alan Cox Date: Tue, 8 Jan 2008 14:55:51 +0000 Subject: pl2303: Fix mode switching regression Cleaning out all the incorrect 'no change made' checks for termios settings showed up a problem with the PL2303. The hardware here seems to lose sync and bits if you tell it to make no changes. This shows up with a real world application. To fix this the driver check for meaningful hardware changes is restored but doing the tests correctly and as a tty layer function so it doesn't get duplicated wrongly everywhere if other drivers turn out to need it. Signed-off-by: Alan Cox Tested-by: Mirko Parthey Signed-off-by: Linus Torvalds --- drivers/usb/serial/pl2303.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'drivers/usb') diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c index cf8add91de05..0da1df9c79bf 100644 --- a/drivers/usb/serial/pl2303.c +++ b/drivers/usb/serial/pl2303.c @@ -483,6 +483,13 @@ static void pl2303_set_termios(struct usb_serial_port *port, } spin_unlock_irqrestore(&priv->lock, flags); + /* The PL2303 is reported to lose bytes if you change + serial settings even to the same values as before. Thus + we actually need to filter in this specific case */ + + if (!tty_termios_hw_change(port->tty->termios, old_termios)) + return; + cflag = port->tty->termios->c_cflag; buf = kzalloc(7, GFP_KERNEL); -- cgit v1.2.3