Re: Garbage on serial console after serial driver loads

From: Russell King
Date: Mon Mar 28 2005 - 14:04:24 EST


On Mon, Mar 28, 2005 at 09:36:52AM -0800, Phil Oester wrote:
> On Sat, Mar 26, 2005 at 03:10:05PM +0000, Russell King wrote:
> > Doesn't matter. The problem is that dwmw2's NS16550A patch (from ages
> > ago) changes the prescaler setting for this device so we can use the
> > higher speed baud rates. This means any programmed divisor (programmed
> > at early serial console initialisation time) suddenly becomes wrong as
> > soon as we fiddle with the prescaler during normal UART initialisation
> > time.
>
> Seems like you are correct, given the below patch fixes the garbage
> output for me.

David,

Is this patch ok for you?

--- linux-standard/drivers/serial/8250.c 2005-03-02 02:37:47.000000000 -0500
+++ linux-dellfw/drivers/serial/8250.c 2005-03-28 12:28:34.560032856 -0500
@@ -698,7 +698,7 @@
serial_outp(up, UART_MCR, status1);

if ((status2 ^ status1) & UART_MCR_LOOP) {
-#ifndef CONFIG_PPC
+#if 0
serial_outp(up, UART_LCR, 0xE0);
status1 = serial_in(up, 0x04); /* EXCR1 */
status1 &= ~0xB0; /* Disable LOCK, mask out PRESL[01] */


--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of: 2.6 Serial core
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