On Fri, Apr 7, 2017 at 9:09 AM, Andrew Lunn <and...@lunn.ch> wrote: > On Fri, Apr 07, 2017 at 07:47:17AM -0700, Tim Harvey wrote: >> Greetings, >> >> I've had a couple of users report that they are getting occasional >> link drops when using IMX6 FEC on our boards which are using a Marvell >> 88E1510 PHY: >> >> [ 9348.474418] fec 2188000.ethernet eth0: MDIO read timeout >> [ 9350.478804] fec 2188000.ethernet eth0: Link is Down >> >> If they bring the interface back up it works fine. >> >> The most recent version of Linux they have tested and seen this on is >> v4.9 with CONFIG_MARVELL_PHY=y >> >> Has anyone else run into this or know what the issue could be? Should >> there be any retries at the MDIO level or above? > > Hi Tim > > MDIO is assumed to be reliable. It failing is bad. > > However, ETIMEOUT is interesting. The MDIO protocol has no flow > control. There is no way for the PHY to delay replying. > > I would suggest you look at the power management code. What i have > seen with the FEC, when using switches attached to the FEC, is that if > the clocks are turned off, you get ETIMEOUT from MDIO. > > Andrew
Andrew, Thanks for the reply. Your talking about suspend/resume power management right? The users reporting this were not using suspend/resume. With regards to clock are you talking about the IPG clock? Is there any other way that would get turned off other than fec suspend/resume? Tim
