On Sun, 2013-10-20 at 01:50 +0200, Petar Bogdanovic wrote: > On Sat, Oct 19, 2013 at 11:27:02PM +0000, Waskiewicz Jr, Peter P wrote: > > > > Disabling SmartSpeed will cause the link negotiation to rely on the > > physical layer to negotiate the link properties. This isn't necessarily > > a bad thing, because link negotiation on 1GbE devices should be solid. > > > > However, there are devices out there that don't conform to the specs, > > which I suspect you're running into. Intel does quite a bit of > > compatibility testing of our parts, and there are cases where we find > > link partners that don't conform to specs for link negotiation. In > > those cases, link either never gets established, or the link speed is > > degraded. SmartSpeed is designed to help you at least get link, rather > > than just fail since the link partner either doesn't implement the spec > > (which is bad), or is flat out broken with regards to the spec (which is > > also bad). > > > > In a nutshell, if you disable SmartSpeed, you can uncover link partners > > that don't behave according to spec. Leaving SmartSpeed enabled will > > allow you to get link, but it may mask the underlying problem of a > > misbehaving link partner. > > I understand, thanks for the explanation. > > Now the only remaining question is how to turn it off without disrupting > something else? I can only see references to smart_speed in conjunction > with LPLU (ich8lan.c, 82571.c, phy.c) and the description of LPLU alone > makes me not want to change anything. :)
That question I will defer to Bruce Allan, who's the maintainer for the e1000e driver. I did the initial SmartSpeed design and implementation for 10GbE devices, so Bruce would be the best resource for how it's integrated into e1000e. -PJ ------------------------------------------------------------------------------ October Webinars: Code for Performance Free Intel webinars can help you accelerate application performance. Explore tips for MPI, OpenMP, advanced profiling, and more. Get the most from the latest Intel processors and coprocessors. See abstracts and register > http://pubads.g.doubleclick.net/gampad/clk?id=60135031&iu=/4140/ostg.clktrk _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired
