On Fri, Jan 06, 2017 at 06:42:24AM +0100, Yegor Yefremov wrote: > On Fri, Jan 6, 2017 at 12:25 AM, Russell King - ARM Linux > <linux@xxxxxxxxxxxxxxx> wrote: > > Another concern with this patch is that the existing phylib "set_eee" > > code is horribly buggy - it just translates the modes from userspace > > into the register value and writes them directly to the register with > > no validation. So it's possible to set modes in the register that the > > hardware doesn't support, and have them advertised to the link partner. > > > > I have a patch which fixes that, restricting (as we do elsewhere) the > > advert according to the EEE supported capabilities retrieved from the > > PCS - maybe the problem here is that the PCS doesn't support support > > EEE in 1000baseT mode? > > > > Out of interest, which PHY is used on this platform? > > > > On the SolidRun boards, they're using AR8035, and have suffered this > > occasional link drop problem. What has been found is that it seems to > > be to do with the timing parameters, and it seemed to only be 1000bT > > that was affected. I don't remember off hand exactly which or what > > the change was they made to stabilise it though, but I can probabily > > find out tomorrow. > > I have different boards with am335x and AR8035 and we had occasional > link drop with both 100 and 1000 speeds. AR8035 has "Smart EEE", which is a PHY specific thing... it's not entirely 802.3 compliant as it doesn't involve the MAC. The Smart EEE control registers are in the PCS MMD - some of this is from people's memories: - 0x805b is the TX wakeup timer. Lower 8 bits for 100base-Tx and upper 8 bits for 1000base-T. - 0x805c and 0x805d. The LPI timer is 24 bit, with the lower 16 bits in 0x805c and the upper 8 in 0x805d. 0x805d bit 8 appears to be the Smart EEE enable bit. What was found was setting the 1000base-T wakeup timer to the same as the 100base-Tx avoided the problems we were seeing, which was only with 1000base-T. (Whether that's because 100base-Tx hasn't been as well tested, I don't know.) SR ended up with 0x1717 in 0x805b. I'd suggest playing around with that register to see if extending the wakeup time has any beneficial effect. Also, I suspect Smart EEE shouldn't be enabled if you have an EEE capable MAC (in which case 0x805d bit 8 should be clear.) I think, however, it defaults to enabled. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
