Re: UART misbehaves under Linkstation/KuroBoxHG

[Guennadi Liakhovetski]

On Wed, 8 Aug 2007, Oncaphillis wrote:

> Greetings,
> 
> I'm trying to compile a 2.6.2x kernel on a Linkstation/KuroBox HG/ppc
> following instructions given under
> http://www.kurobox.com/mwiki/index.php/Kurobox_support_in_stock_2.6_kernels

Wow, congratulations! Not too many endevour into this land, and even fewer 
succeed:-) You'd probably be better off asking this on linuxppc-dev, but 
anyway...

> and get weired settings and errors from the serial device (UART 16550A).
> 
> Under the 2.4.17 kernel provided by the Kurobox manufacturer it gets IRQS in
> the range of 137/138 under 2.6.22 for the linkstation it gets IRQS 17/18 and
> the serial device behaves fishy

That interrupt numbers are different as under 2.4 is correct, however, I 
get 16 and 17 for ttyS0 and ttyS1 on a kuroboxHG, are you sure you're 
getting 17 and 18?

> communication errors
> 
> "to much work in IRQ 16"

And here you get IRQ 16, which indeed should be ttyS0. And ttyS0 is 
connected to the power-management microcontroller (AVR). Wait, what 
userspace are you running? Have you swapped ttyS0 and ttyS1 everywhere? in 
/etc/inittab for example? Besides, if you are running any vendor provided 
(or community) tools to handle the AVR - they use ttyS1 by default, as it 
was under 2.4 ans under "traditional" 2.6, whereas the 2.6 mainline kernel 
for kurobox/linkstation uses the traditional for these CPUs port 
numbering. I think this is your problem. Some user-space programme(s) are 
accessing wrong tty.

Thanks
Guennadi
---
Guennadi Liakhovetski
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