On Fri, Oct 23, 2020 at 08:29:59AM +0200, Juerg Haefliger wrote: > On Wed, 21 Oct 2020 21:35:48 +0200 > Andrew Lunn <[email protected]> wrote: > > > On Wed, Oct 21, 2020 at 05:00:53PM +0200, Juerg Haefliger wrote: > > > Hi, > > > > > > If the lan78xx driver is compiled into the kernel and the network cable is > > > plugged in at boot, /sys/class/net/eth0/carrier is stuck at 1 and doesn't > > > toggle if the cable is unplugged and replugged. > > > > > > If the network cable is *not* plugged in at boot, all seems to work fine. > > > I.e., post-boot cable plugs and unplugs toggle the carrier flag. > > > > > > Also, everything seems to work fine if the driver is compiled as a module. > > > > > > There's an older ticket for the raspi kernel [1] but I've just tested this > > > with a 5.8 kernel on a Pi 3B+ and still see that behavior. > > > > Hi Jürg > > Hi Andrew, > > > > Could you check if a different PHY driver is being used when it is > > built and broken vs module or built in and working. > > > > Look at /sys/class/net/eth0/phydev/driver > > There's no such file.
I _think_ that means it is using genphy, the generic PHY driver, not a specific vendor PHY driver? What does /sys/class/net/eth0/phydev/phy_id contain. > Given that all works fine as long as the cable is unplugged at boot points > more towards a race at boot or incorrect initialization sequence or something. Could be. Could you run mii-tool -vv eth0 in the good and bad case. Andrew
