Re: UART misbehaves under Linkstation/KuroBoxHG

Guennadi Liakhovetski
2007-08-08T21:41:25Z

On Wed, 8 Aug 2007, Oncaphillis wrote:

> So that's ok ? No misconfiguration ? And that setserial tells
> me the port is 0x000 ?

Yes, everything looks ok, don't know why, setserial reports 0 here too,
but it doesn't cause me any (visible) problems.

> I thought the dts file which
> comes with the linkstation kernel describes the ports and IRQs
> but poking there didn't change anything. It seems like the kernel
> is ignoring the serial settings in the dts-file (which I do not
> realy understand) all together.

Believe me, it doesn't ignore them:-) Don't know what exactly you were
poking at there, but it should be quite easy to break it by changing
clocks / address / irq...

> I started with a debian distro
> http://www.kurobox.com/mwiki/index.php/Debian_sylver
>
> Hmm I tried my very best to eliminate this everywhere. Actually I
> resurrected the ARV00 device by creating a soft link to a ttySx
> with during bootup within the udev filesystem.
>
> <snip>
> if [ ! -e /dev/AVR00 ];then
> cat /proc/tty/driver/serial | grep 80004500 | grep -q 0:
> && AVR=/dev/ttyS0 || AVR=/dev/ttyS1
> echo "Making AVR00 link to "$AVR;
> ln -s $AVR /dev/AVR00
> fi;
> </snip>
>
> Stole the trick from the avr_evtd startup script...

Well, just do "ls -l /dev/AVR00", then "lsof /dev/ttyS0".

In principle, as mentioned elsewhere before, you don't need any daemons on
linkstation/kurobox now for "basic" operation, i.e., the kernel disables
the watchdog on startup, and properly sends reboot and power-off commands
to the AVR itself without any userspace support. So, at least for a test,
you could stop all those daemons. You need them though if you want to use
the buttons to power down / reboot / whatever, do other fancy things with
the AVR...

Another possible reason why, for example, your stty misbehaves, maybe it
is somehow broken in that distro? I am just using etch and things work
pretty well.

Thanks
Guennadi
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Guennadi Liakhovetski