Re: [PATCH] net: bcmgenet: Return not supported if we don't have a WoL IRQ

[Peter Robinson <pbrobinson@gmail.com>]

> On 2/22/2022 1:53 AM, Peter Robinson wrote:
> > The ethtool WoL enable function wasn't checking if the device
> > has the optional WoL IRQ and hence on platforms such as the
> > Raspberry Pi 4 which had working ethernet prior to the last
> > fix regressed with the last fix, so also check if we have a
> > WoL IRQ there and return ENOTSUPP if not.
> >
> > Fixes: 9deb48b53e7f ("bcmgenet: add WOL IRQ check")
> > Fixes: 8562056f267d ("net: bcmgenet: request Wake-on-LAN interrupt")
> > Signed-off-by: Peter Robinson <pbrobinson@gmail.com>
> > Suggested-by: Javier Martinez Canillas <javierm@redhat.com>
> > ---
> >   drivers/net/ethernet/broadcom/genet/bcmgenet_wol.c | 4 ++++
> >   1 file changed, 4 insertions(+)
> >
> > We're seeing this crash on the Raspberry Pi 4 series of devices on
> > Fedora on 5.17-rc with the top Fixes patch and wired ethernet doesn't work.
>
> Are you positive these two things are related to one another? The
> transmit queue timeout means that the TX DMA interrupt is not firing up
> what is the relationship with the absence/presence of the Wake-on-LAN
> interrupt line?

The first test I did was revert 9deb48b53e7f and the problem went
away, then poked at a few bits and the patch also fixes it without
having to revert the other fix. I don't know the HW well enough to
know more.

It seems there's other fixes/improvements that could be done around
WOL in the driver, the bcm2711 SoC at least in the upstream DT doesn't
support/implement a WOL IRQ, yet the RPi4 reports it supports WOL.

This fix at least makes it work again in 5.17, I think improvements
can be looked at later by something that actually knows their way
around the driver and IP.

Peter

[1] https://elixir.bootlin.com/linux/v5.17-rc5/source/arch/arm/boot/dts/bcm2711.dtsi#L541

> At any rate:
>
> Acked-by: Florian Fainelli <f.fainelli@gmail.com>
> --
> Florian