Date: Tue, 23 Mar 2010 16:38:40 -0700 From: Marcel Moolenaar <xcllnt@mac.com> To: pyunyh@gmail.com Cc: powerpc@freebsd.org, embedded@freebsd.org, "M. Warner Losh" <imp@bsdimp.com> Subject: Re: Anyone using BOOTP with latest current (Book-E)? Message-ID: <00BE3C94-8C04-4E00-9617-1DB07C7FAF42@mac.com> In-Reply-To: <20100323230351.GI1278@michelle.cdnetworks.com> References: <B7BAFA66-33DF-4EAB-835D-50BEEF7919D0@mac.com> <4BA8CF0E.50201@freebsd.org> <20100323.094126.787670930724128348.imp@bsdimp.com> <E210061E-5EE8-42C9-9B20-9788AB6F836B@mac.com> <20100323230351.GI1278@michelle.cdnetworks.com>
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On Mar 23, 2010, at 4:03 PM, Pyun YongHyeon wrote:
>> I looked at whether we restart autoneg if the PHY is in autoneg already because
>> I've seen at Juniper how that can contribute to excessive link flaps and even
>> excessive autoneg completion times (>40 seconds) depending on the switch and
>> did this:
>>
>> Index: dev/mii/ciphy.c
>> ===================================================================
>> --- dev/mii/ciphy.c (revision 205451)
>> +++ dev/mii/ciphy.c (working copy)
>> @@ -176,13 +176,11 @@
>>
>> switch (IFM_SUBTYPE(ife->ifm_media)) {
>> case IFM_AUTO:
>> -#ifdef foo
>> /*
>> * If we're already in auto mode, just return.
>> */
>> if (PHY_READ(sc, CIPHY_MII_BMCR) & CIPHY_BMCR_AUTOEN)
>> return (0);
>> -#endif
>> (void) mii_phy_auto(sc);
>> break;
>> case IFM_1000_T:
>>
>>
>> Apparently the author already considered the same and it does resolve the issue.
>> Anyone see any concerns with my applying this patch?
>>
>
> I'm not sure but I guess the #ifdef foo block could be completely
> nuked. The auto-negotiation timeout is set to 17 seconds for
> gigabit link and ciphy(4) will reprogram BMCR if auto-negotiation
> was not resolved after that timeout.
That's besides the point. calling mii_phy_auto() while autoneg is
ongoing aborts the autoneg and restarts it. This causes a link flap
and makes some switches cranky.
What the patch does is to not enable autoneg when autoneg is already
enabled so that we don't interfere with the autoneg handshake.
--
Marcel Moolenaar
xcllnt@mac.com
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