Advice on troubleshooting an issue

[bceverly]

Hi everyone,

I've noticed on my 13" Retina Macbook Pro that my urtwm WiFi suddenly stops working. It doesn't detatch it just stops routing packets. I can generally solve it by unplugging the USB dongle (rebooting doesn't seem to help) and plugging it back in. It seems to be related more to lack of traffic on the interface versus failing after a certain period of time. I've tried using -powersave on ifconfig but that didn't address it.

I have a second issue with the wired Ethernet adapter in my hppa C3700 where I'm getting watchdog timeouts.

My question is this - what troubleshooting can I do or what data can I gather to help identify where the problem is occurring or at the very least provide the right data to the bugs@ list to help point them in the right direction?

Any help would be appreciated!

[jggimi]

WLAN NIC communication problems

These are tough to debug. We have the same model amd64 laptop, and my rtwn(4) NIC that will do the same thing every once and awhile. I assume yours is working fine. Both of us might find enabling debugging tools in our kernels would help. RTWN_DEBUG for me, and URTWN_DEBUG for you. We'd need to build kernels with these debug flags enabled -- see the -D option of make(1).

If these things were easily repeatable, we could capture 802.11 radio traffic with tcpdump at the same time. In my case it's intermittent, and easily restartable.

Watchdog timeouts on NICs

These are sometimes hardware problems -- in some instances it can be due to physical media issues (cable failures), but more often when it is hardware it's a NIC media adapter -- and these are integrated in the NICs. Sometimes there are poor slot connections, and problems like these can be cured by reseating a NIC card.

A debugging flag for your wired Ethernet can be found in the driver source code. For example, I found the RTWN_DEBUG flag in /usr/src/sys/dev/pci/if_rtwn.c.

[jggimi]

OK, I'm taking my own advice, and building a kernel with RTWN_DEBUG.

The make(1) -D option is not used. Instead, build a custom kernel with option XXX_DEBUG.

For example:

$ cd /usr/src/sys/arch/amd64/conf
$ cp GENERIC.MP RTWN
$ echo option RTWN_DEBUG >> RTWN
$ config RTWN
$ cd ../compile/RTWN
$ make

[jggimi]

I'm eating my own dog food, as they say. Running the custom kernel, and have enabled the debugging variable rtwn_debug via ddb(4). You can do that by entering ddb() from the console via sysctl settings, or by booting the kernel with -d.

According to if_rtwn.c, there are multipld debugging levels. 0 = none, 1 or more enables printf reporting, 2+ dumps ROM contents, 4+ dumps transmit power levels. Every driver may be different, so review your applicable driver source.

[bceverly]

@jggimi

You rock (as always)! Thank you so much for the suggestions. I now have some fun work for the weekend.

:-)