Re: [BUG bisect] Missing Micrel driver on VF50 (net: phy: check return code when requesting PHY driver module)

[Krzysztof Kozlowski]

On Fri, 18 Jan 2019 at 09:39, Krzysztof Kozlowski <krzk@xxxxxxxxxx> wrote:
>
> Hi,
>
> On today's next (next-20190118) my Colibri VF50 board fails to boot up
> from network (DHCP, NFSv4 root). Looks like missing network adapter.
> Expected:
> [ 3.041773] Micrel KSZ8041 400d1000.ethernet-1:00: attached PHY driver
> [Micrel KSZ8041] (mii_bus:phy_addr=400d1000.ethernet-1:00, irq=POLL)
>
> Result:
> [ 15.614964] Root-NFS: no NFS server address
> [ 15.619353] VFS: Unable to mount root fs via NFS, trying floppy.
> [ 15.626762] VFS: Cannot open root device "nfs" or unknown-block(2,0): error -6
> [ 15.634252] Please append a correct "root=" boot option; here are the
> available partitions:
> [ 15.642791] 0100 16384 ram0
> [ 15.642804] (driver?)
> [ 15.649076] Kernel panic - not syncing: VFS: Unable to mount root fs
> on unknown-block(2,0)
> [ 15.657423] ---[ end Kernel panic - not syncing: VFS: Unable to mount
> root fs on unknown-block(2,0) ]---
>
> Bisect pointed to:
>     net: phy: check return code when requesting PHY driver module

I see now in the logs:
[ 2.436822] mdio_bus 400d1000.ethernet-1:00: error -2 loading PHY
driver module for ID 0x00221513
which is kind of misleading. There is no initramfs so there is no
usermod library at this point. It is not needed. This seems to break
all DHCP/NFS root boots without initrd/initramfs.

Best regards,
Krzysztof