Commit 1401ebda authored Apr 27, 2016 by David Müller Committed by Greg Kroah-Hartman Jun 01, 2016

serial: 8250_pci: fix divide error bug if baud rate is 0

commit 6f210c18c1c0f016772c8cd51ae12a02bfb9e7ef upstream.

Since commit 21947ba6 ("serial: 8250_pci: replace switch-case by
formula"), the 8250 driver crashes in the byt_set_termios() function
with a divide error. This is caused by the fact that a baud rate of 0 (B0)
is not handled properly. Fix it by falling back to B9600 in this case.

Signed-off-by: David Müller <d.mueller@elsoft.ch>
Fixes: 21947ba6 ("serial: 8250_pci: replace switch-case by formula")
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 71378785

drivers/tty/serial/8250/8250_pci.c

+3 −0

Original line number	Original line	Diff line number	Diff line
	@@ -1401,6 +1401,9 @@ byt_set_termios(struct uart_port p, struct ktermios termios,
	unsigned long m, n;		unsigned long m, n;
	u32 reg;		u32 reg;

			/* Gracefully handle the B0 case: fall back to B9600 */
			fuart = fuart ? fuart : 9600 * 16;

	/* Get Fuart closer to Fref */		/* Get Fuart closer to Fref */
	fuart *= rounddown_pow_of_two(fref / fuart);		fuart *= rounddown_pow_of_two(fref / fuart);