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
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
I'm wondering if in the builtin case, it is using genphy, but with
modules it uses a more specific vendor driver.
Andrew
