On Wed, 21 Oct 2020 21:35:48 +0200 Andrew Lunn <and...@lunn.ch> 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'm wondering if in the builtin case, it is using genphy, but with > modules it uses a more specific vendor driver. 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. ...Juerg > Andrew
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