> -----Original Message----- > From: Waskiewicz Jr, Peter P [mailto:[email protected]] > Sent: Monday, March 11, 2013 10:19 PM > To: [email protected] > Cc: [email protected]; Tantilov, Emil S > Subject: Re: [E1000-devel] ixgbe for 82599, how to disable autoneg? > > On 3/11/2013 8:38 PM, [email protected] wrote: > > My understanding is that this does not disable auto-negotiation but > > rather just sets what is advertised during auto-negotiation as supported > rates. > > > > We are working with an rather odd experimental system where we are > > trying to create a 10G link between two 82599 based NICs (ATTO > > FastFrame NS12 with dual SFP+ modules) over an optical link with 100 > > msec of latency in each direction. We are experiencing long delays in > > getting a link light that we believe is related to auto-negotiation. > > We would like to try running without auto-negotiation. It appears the > > 82599 controller supports, so > > > > Does the 82599 support 1GbE and 10GbE via SFP+ without auto- > negotiation? > > > > I was hoping to get some guidance on how to go about modifying the > > ixgbe driver so that I can try 1G and 10G without auto-negotiation. > > Ah, so you're using dual-speed optics. What you're referring to isn't auto- > negotiation per se, it's what we call Smart Speed. Since 10G fiber doesn't > have a speed auto-negotiation via spec, we came up with this algorithm to do > the speed detection and downshift. > > I would search the code (ixgbe_82599.c for example) and set smart_speed in > the PHY struct to smart_speed_off when in the case of multispeed_fiber. > > Hope this helps, > -PJ >
Smartspeed may well be causing some latency but it would only come into play on a backplane device. And since you mentioned SFP+ it leads me to believe that you're not on one. PJ point was very valid however in that 10G doesn't do autoneg for say. For multi-speed fiber we instead "try" all the speeds that you have advertised (like Emil mentioned before). So in the case of 0x1020 (10G and 1G) we will try 10G - 1G - 10G. So this could well be causing latency on your 1G connection if we first attempt a 10G. You could prevent this by only advertising the speed you want to connect to likewise have your peer do the same. Now from your example code you sent I don't believe would work, once again I'm assuming you are using SFP+ fiber. If that is the case your example was using KX and KX4 which I don't believe would work. If you are only worried about getting link light up faster and don't care about auto try, you could also disable the laser functions in ixgbe_init_mac_link_ops_82599() much like we do if MNG FW is running. Then the link would turn on (assuming we could get link) in probe and not turn off with a 'ifconfig down'. Thanks, Don Skidmore <[email protected]> ------------------------------------------------------------------------------ Symantec Endpoint Protection 12 positioned as A LEADER in The Forrester Wave(TM): Endpoint Security, Q1 2013 and "remains a good choice" in the endpoint security space. For insight on selecting the right partner to tackle endpoint security challenges, access the full report. http://p.sf.net/sfu/symantec-dev2dev _______________________________________________ E1000-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
