Messages in this thread | | | Date | Fri, 27 Mar 2015 16:52:57 +0300 | From | Stas Sergeev <> | Subject | Re: [PATCH 0/6] mvneta: SGMII-based in-band link state signaling |
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27.03.2015 16:39, Andrew Lunn пишет: > On Fri, Mar 27, 2015 at 04:28:28PM +0300, Stas Sergeev wrote: >> Hello. >> >> Currently the fixed-link DT binding is pre-configured and >> cannot be changed in run-time. This means the cable unplug >> events are not being detected, and the link parameters can't >> be negotiated. > > O.K, i will ask the dumb question.... > > Isn't fixed-link supposed to be used for links which are fixed? > Why would a fixed-link change? Hi, my current understanding of fixed-link DT binding is that it is actually just an MDIO-less link, but not more fixed than that. I made a patch out of that assumption. Why I think that way is because fixed-link internally uses a fixed_phy driver - the one that actually allows a state updates and emulates MDIO on top of these. So I just exploited that already coded capability. I think any other approach will require much more work.
> The use cases i've seen for this is when you are connecting the MAC to > a Switch. The link is configured to its fastest mode and then left > alone. > > Please could you give some more background information. What do you > have on the other end of this fixed link which keeps changing? > Obviously not a switch. Normal PHY, not a switch. But there is no MDIO, because SGMII AFAIK doesn't need MDIO. SGMII has in-band status, but for some reason it seems currently linux is not ready for such setup - this is what my patch addresses. Or maybe I am missing something?
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