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

[Krzysztof Kozlowski <krzk@kernel.org>]

On Tue, 22 Jan 2019 at 14:52, Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> Hi Heiner,
>
> On Fri, Jan 18, 2019 at 9:58 PM Heiner Kallweit <hkallweit1@gmail.com> wrote:
> > On 18.01.2019 09:48, Krzysztof Kozlowski wrote:
> > > On Fri, 18 Jan 2019 at 09:39, Krzysztof Kozlowski <krzk@kernel.org> wrote:
> > >> 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.
> > >
> > Thanks for the report. Could you please provide your kernel config
> > and the syslog of a boot before or w/o the patch in question?
> >
> > If you boot via nfs then I'd expect that the PHY driver is built-in and
> > not a module. Therefore it's not fully clear to me yet why
> > request_module() returns -ENOENT.
>
> I'm seeing the same booting nfsroot on several Renesas boards.
> E.g. on r8a7791/koelsch:
>
>     mdio_bus ee700000.ethernet-ffffffff:01: error -2 loading PHY
> driver module for ID 0x00221537
>     sh-eth ee700000.ethernet: MDIO init failed: -2
>

Hi Geert,

There is a follow up patch:
https://www.spinics.net/lists/netdev/msg545573.html

Best regards,
Krzysztof