Rpi3: no ethernet in 4.13: bisected to patch 'USB: of: fix root-hub device-tree node handling'

[Johan Hovold]

On Wed, Aug 02, 2017 at 01:10:33PM +0200, Stefan Wahren wrote:
> Am 02.08.2017 um 09:03 schrieb Hans Verkuil:
> > When testing with my Raspberry Pi 3 and the 4.13-rcX mainline kernel
> > I discovered that there was no ethernet. After bisecting I got to commit
> > 2bf69867 ('USB: of: fix root-hub device-tree node handling').
> >
> > With that commit lsusb outputs:
> >
> > rpi3: ~ # lsusb
> > Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
> >
> > After reverting just that commit (I'm on 4.13-rc3 now) ethernet is
> > restored and lsusb gives me:
> >
> > rpi3: ~ $ lsusb
> > Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp. SMSC9512/9514 Fast Ethernet Adapter
> > Bus 001 Device 002: ID 0424:9514 Standard Microsystems Corp. SMC9514 Hub
> > Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
> >
> > I don't speak USB, so I have no idea why this patch causes these issues,
> > but I am happy to test patches.
> 
> Thanks for finding.
> 
> Just a note, Andreas Färber also found a regression in 4.13-rc1, which
> is related to USB & DMA [1].
> Unfortunately i wasn't able to bisect this issue. I think it's related
> to the configuration.
> 
> [1] -
> http://lists.infradead.org/pipermail/linux-rpi-kernel/2017-July/006658.html

Ah, thanks, that makes more sense (at least if Hans is also getting
those "Cannot do DMA to address" errors during probe).

It should be commit 2bf698671205 ("USB: of: fix root-hub device-tree
node handling") interacting with 09515ef5ddad ("of/acpi: Configure dma
operations at probe time for platform/amba/pci bus devices").

Let me take a closer look.

Thanks,
Johan