Date: Thu, 31 Jan 2013 14:29:18 -0800 From: Neel Natu <neelnatu@gmail.com> To: Jack Vogel <jfvogel@gmail.com> Cc: Jack F Vogel <jfv@freebsd.org>, freebsd-net <freebsd-net@freebsd.org>, Ryan Stone <rysto32@gmail.com> Subject: Re: e1000 serdes link flap Message-ID: <CAFgRE9GqRKR9DeEPPRGPbbVWemO965=-Mu5PQKXOOJmo3fzAYg@mail.gmail.com> In-Reply-To: <CAFOYbckpz_Ujj6Xfqrsx6jwz8Y9CdwyoN%2BGGt75fCO%2BeO9jPZQ@mail.gmail.com> References: <CAFgRE9EpskSJ=PHG0qhDoDE6eP1_yXTidOwnhr8q-M=G3UCHSQ@mail.gmail.com> <CAFMmRNzA-s4T1T=NCZL1fWqop0Hr-WpPwJQfat1E-qugb4Jdcw@mail.gmail.com> <CAFgRE9FBgGSy4EQJrsKomZgwTTZmweeHpYHER4qWCP%2Bykr8sdw@mail.gmail.com> <CAFOYbckpz_Ujj6Xfqrsx6jwz8Y9CdwyoN%2BGGt75fCO%2BeO9jPZQ@mail.gmail.com>
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Hi Jack, On Thu, Jan 31, 2013 at 12:03 PM, Jack Vogel <jfvogel@gmail.com> wrote: > I will not commit this patch, this is shared code used by all the different > OS's we do > drivers for, and it is unnecessary in any case, because the latest version > of the internal > code has this resolved.... So, I will soon do some updates to the e1000 > drivers anyway > and as part of that I will sync the shared code base with the latest, this > should address > the issue... OK? Sounds good. best Neel > > Cheers, > > Jack > > > > On Mon, Jan 28, 2013 at 8:14 PM, Neel Natu <neelnatu@gmail.com> wrote: >> >> Hi Jack, >> >> On Wed, Jan 23, 2013 at 2:58 PM, Ryan Stone <rysto32@gmail.com> wrote: >> > On Wed, Jan 23, 2013 at 2:13 AM, Neel Natu <neelnatu@gmail.com> wrote: >> >> >> >> Hi, >> >> >> >> I am running into a problem in head with the e1000 link state >> >> detection logic attached to a 82571EB serdes controller. >> >> >> >> The symptom is that the link state keeps flapping between "up" and >> >> "down". >> >> >> >> After I enabled the debug output in >> >> 'e1000_check_for_serdes_link_82571()' this is what I see: >> >> <snip> >> >> e1000_check_for_serdes_link_82571 >> >> ctrl = 0x4c0241, status = 0x803a7, rxcw = 0x44000000 >> >> FORCED_UP -> AN_PROG >> >> em6: link state changed to DOWN >> >> e1000_check_for_serdes_link_82571 >> >> ctrl = 0x4c0201, status = 0x803a4, rxcw = 0x44000000 >> >> AN_PROG -> FORCED_UP >> >> em6: link state changed to UP >> >> e1000_check_for_serdes_link_82571 >> >> ctrl = 0x4c0241, status = 0x803a7, rxcw = 0x44000000 >> >> FORCED_UP -> AN_PROG >> >> em6: link state changed to DOWN >> >> </snip> >> >> >> >> The problem goes away if I apply the following patch to bring the link >> >> state detection logic in line with the e1000e driver in Linux: >> >> >> >> Index: e1000_82571.c >> >> =================================================================== >> >> --- e1000_82571.c (revision 245766) >> >> +++ e1000_82571.c (working copy) >> >> @@ -1712,10 +1712,8 @@ >> >> * auto-negotiation in the TXCW register and >> >> disable >> >> * forced link in the Device Control register >> >> in >> >> an >> >> * attempt to auto-negotiate with our link >> >> partner. >> >> - * If the partner code word is null, stop >> >> forcing >> >> - * and restart auto negotiation. >> >> */ >> >> - if ((rxcw & E1000_RXCW_C) || !(rxcw & >> >> E1000_RXCW_CW)) { >> >> + if ((rxcw & E1000_RXCW_C) != 0) { >> >> /* Enable autoneg, and unforce link up >> >> */ >> >> E1000_WRITE_REG(hw, E1000_TXCW, >> >> mac->txcw); >> >> E1000_WRITE_REG(hw, E1000_CTRL, >> >> >> >> I am not sure why the !(rxcw & E1000_RXCW_CW) check was added and the >> >> e1000 SDM does not have any more information. >> >> >> >> Jack, can you take a look at the patch and commit if it looks alright? >> > >> > >> > I have this change applied internally. I thought that it was something >> > funny in my environment, so I never tried to push it upstream. Sorry >> > for >> > costing you time in having to debug this. :( >> >> Are you planning to commit this patch? >> >> I am happy to get you more information from my system if it helps you >> get to the bottom of this quicker. >> >> best >> Neel > >
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