Date: Sun, 14 Jul 2013 21:52:38 +0200 From: Andreas Longwitz <longwitz@incore.de> To: pyunyh@gmail.com Cc: freebsd-net@freebsd.org Subject: Re: sis(4) flow control Message-ID: <51E30186.9050707@incore.de> In-Reply-To: <20130714100347.GA1105@michelle.cdnetworks.com> References: <51DC1599.8040805@incore.de> <20130710023512.GB2753@michelle.cdnetworks.com> <51DDDDAB.6070100@incore.de> <20130711002557.GA6697@michelle.cdnetworks.com> <51E1B8F0.5030100@incore.de> <20130714100347.GA1105@michelle.cdnetworks.com>
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Yonghyeon PYUN wrote:
>> Maybe there is a bug in vr(4) that generates the hang, but why is
>
> Probably yes and I shall have to narrow down the issue.
One more hint: No hang - but of course no TX support - anymore, when I use
--- if_vr.c.orig 2013-06-25 09:58:29.000000000 +0200
+++ if_vr.c 2013-07-14 18:09:12.000000000 +0200
@@ -351,7 +351,6 @@
fc |= VR_FLOWCR1_RXPAUSE;
if ((IFM_OPTIONS(mii->mii_media_active) &
IFM_ETH_TXPAUSE) != 0) {
- fc |= VR_FLOWCR1_TXPAUSE;
sc->vr_flags |= VR_F_TXPAUSE;
}
CSR_WRITE_1(sc, VR_FLOWCR1, fc);
Probably the RX pause frames will work with this patch.
>> negotiation of flowcontrol on vr(4) not done at boot time as shown for
>> msk(4) ?
>>
>
> msk(4) supported flow-control from day 1 with a hack and it was
> re-implemented later with proper way such that it always announces
> flow-control. However for other drivers(i.e vr(4)) that didn't
> support the feature in the beginning, you have to explicitly enable
> the feature. The decision was made to provide compatibility and to
> not introduce POLA.
Thanks for clarification, I see the flag MIIF_FORCEPAUSE does the job.
>> If you need more information about the hang let me know.
>
> I guess it would be good idea to use a link partner that shows
> hardware MAC statistics. If your switch provides such information
> that's fine. If you use direct connection between two hosts without
> switch, use other network drivers(most gigabit controllers support
> hardware MAC counters).
I can easy realize to use my laptop with msk(4) as a link partner for my
soekris box with vr(4).
--
Dr. Andreas Longwitz
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