Re: UART misbehaves under Linkstation/KuroBoxHG

From: Oncaphillis
Date: Wed Aug 08 2007 - 18:04:53 EST


Guennadi Liakhovetski wrote:
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".


Oh.... that's something I should have thought about (shaking my
head)

I hope I found the the misconfigured part. I didn't look
at /etc/inittab. It opens a getty on /dev/ttyS0. That
might do the trick. Have to recompile my kernel right now with
standard config to check this out.

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...

Well ... it doesn't seem to need the daemons but at least
the kuro_boot script or something similar has to be executed
once sending the right init strings to the AVR or your system
reboots after a few minutes at least on my box.

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
---
Guennadi Liakhovetski

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