debugging network device driver

Pyun YongHyeon pyunyh at gmail.com
Sun Feb 22 17:20:13 PST 2009


On Sun, Feb 22, 2009 at 09:00:29AM +0100, Tesch Zoltan wrote:
> Hi,
> 
> I have just tried to port SiS190 Linux driver to FreebBSD. It seems to
> me that this driver looks like r8169 and for this reason my port is
> based on the "re" device driver of FreeBSD 6.4.

Hmm, I have no idea why SiS190 is similar to RTL8169. Both
controllers have small set of registers though.

> I can load the module, attach to SiS190 device, miibus and phy but when
> I try to set up the interface with ifconfig (ifconfig sis0 up) the
> computer freezes. I have tried to print status information from my
> driver (using printf`s in the code) but the last record in the log is
> that miibus_readreg returned a good value, no other record is logged
> into the system log.
> 

It's hard to say what was wrong here. Datasheet is not available
to open source developers and the controller seem to have severe
alignment restrictions as well as lack of auto-padding.

> My questions:
> Is there any way to switch to kernel debug mode in this situation to see
> what happened or is it possible to run  the module under the supervision
> of kernel debugger running on the machine, because this laptop has no
> serial line or any other network interface.
> 

ktr(4) is much better than printfs. Btw there was a post for
SiS190 driver so you can reference his work.
http://lists.freebsd.org/pipermail/freebsd-drivers/2008-April/000685.html

Having a wired/wireless USB network controller would make your
life easier.


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