Getting the kernel to let go of my UART!

[Oleksandr Tymoshenko]

Oleksandr Tymoshenko (gonzo at bluezbox.com) wrote:
> Dustin Marquess (dmarquess at gmail.com) wrote:
> > Okay, maybe the console thing was a red herring then.
> > 
> > It's not marking it as a console at all anymore, but something is
> > still locking the baud rate to 115200.  Even though stty and minicom
> > are both set to 9600, anything set/received at 9600 doesn't work/is
> > garbled.  If I set it to 115200, it works fine.  I had wrongly assumed
> > it was because of it marking it as a console (since the console line
> > in dmesg said 115200).
> > 
> > Device map? enable_uart=1 aka core_freq= maybe? I'll try tinkering..
> 
> It might be a problem with the driver itself. From a quick glance,
> PL011 driver sets baudrate only if it has reference clock frequency
> which doesn't seem to be the case for RPi. If reference clock
> frequency is unknown divider register is left untouched.
> 
> According to this document: http://elinux.org/RPiconfig you can
> set initial baudrate in config.txt using init_uart_baud variable

Also if you use u-boot divider register can be overridden by U-Boot
intialization routine. 

-- 
gonzo