vr(4) troubles for AMD Geode CS5536 chipset

Eugene Grosbein egrosbein at rdtc.ru
Mon Sep 3 04:56:44 UTC 2012


04.09.2012 01:40, YongHyeon PYUN пишет:

>> Presently, every day my WAN vr interface stops running correctly:
>> sometimes it stops receiving all packets - tcpdump shows none of them.
>> Sometimes, it receives some but with great delay - up to 10 seconds (not miliseconds)
>> and even more. tcpdump shows that delay occurs on receive path.
>> Sometimes, it even rearranges packets - tcpdump shows that some incoming ICMP echo requests
>> with lower sequence numbers come in later that already answered higher-numbered requests.
> 
> Hmm, it seems driver's consumer/producer index of RX path were
> corrupted.

Have you any idea how to find that out for sure?
Add some debug printfs or KASSERT, may be?
I'm ready to test.

> By chance, did vr(4) spew some kind of diagnostics messages to
> console?  If I remember correctly, vr(4) automatically restarts
> controller and show these errors when it detects abnormal
> condition. Abnormal conditions for vr(4) would be:
>  - TX/RX MAC stuck
>  - RX MAC stop due to FIFO overflow or no RX buffers
>  - PCI bus errors
>  - TX abort
>  - TX underrun
> 

None. I've read its source and learned it prints its debug
to the kernel dmesg buffer with sysctl dev.vr.1.stats=1
and done that before, during and after noted failure -
all counters are zero except of good frames conters (in/out).

Eugene Grosbein


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