bwn + BETA3/ppc = very unstable

[Adrian Chadd]

On 3 October 2011 12:43, Roman Bogorodskiy <novel at freebsd.org> wrote:
>  Roman Bogorodskiy wrote:

> Hm, I have applied a fix similar to this one:
>
> http://www.openbsd.org/cgi-bin/cvsweb/src/sys/dev/ic/bwi.c.diff?r1=1.88;r2=1.89
>
> I'm not sure if it's a coincidence or not, but I had no panics since
> then. Packet loss rate are still very high - first packets go through
> without losses, but eventually loss rate goes up.

It sounds like a calibration issue.

> Now uptime is 1 hour and loss rate is about 80-85%.
>
> Any directions how can I debug this?

Well, firstly, can you please do up a patch against -HEAD? I'll commit
it to FreeBSD-HEAD ASAP and then include it in the list of things I
want to backmerge into -9.

Debugging this - I'd first isolate it to whether it is:

* TX issues;
* RX issues;
* or both TX and RX issues.

I suggest liberal use of iperf in UDP mode to TX things. It's a bit
difficult as TX'ing a one way UDP stream also involves RX'ing an ACK
from the remote end, so it isn't a 100% guaranteed way of debugging
it. But it hopefully will show it's either TX or RX related.

I'd also enable BWI_DEBUG and then flip on the relevant bits that let
you debug the attach and configuration bits (BWI_DBG_RF,
BWI_DBG_TXPOWER, BWI_DBG_ATTACH).
In fact, enable both BWI_DEBUG and BWI_DEBUG_VERBOSE in your kernel
config and rebuild.

The BWI_DBG bits are defined in if_bwivar.h.

Adrian