Re: Garbage on serial console after serial driver loads

From: Phil Oester
Date: Sat Mar 26 2005 - 10:56:58 EST


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.

FWIW, I see the same thing here on some Dell Poweredge boxes:

serio: i8042 AUX port at 0x60,0x64 irq 12
serio: i8042 KBD port at 0x60,0x64 irq 1
Serial: 8250/16550 driver $Revision: 1.90 $ 8 ports, IRQ sharing disabled
ttyS0 at I/O 0x3f8 (irq = 4) is a NS16550A
ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
<garbage>

But intererstingly, on identical boxes, the garbage only appears on
those hooked up to a PortMaster device - those using a Cyclades never
display this problem. (???)

Phil
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