Bug#864807: b53_mdio module doesn't get loaded automatically on Lamobo R1 (was: debian-installer: Lamobo R1 requires modprobe b53_mdio)

[Karsten Merker <merker@debian.org>]

control: retitle 864807 b53_mdio module doesn't get loaded automatically on Lamobo R1
control: reassign 864807 src:linux 4.9.30-2

On Thu, Jun 15, 2017 at 08:34:34AM +0200, Heinrich Schuchardt wrote:

> Package: debian-installer
> Version: stretch
> Severity: normal
> 
> Dear Maintainer,
> 
> the Lamobo R1 is an Arm system based on the Amlogic A20.

s/Amlogic/Allwinner/ :-)

> The network interface of the A20 is connected to a switch.
> If the switch is not configured there is no external
> network access and subsequently a network install fails.
> 
> On an installed system it is sufficient to have a line
> in /etc/modules:
> b53_mdio
> 
> I suggest the following corrections to the installer:
> 
> The initrd.img should include the b53_mdio module and its
> prerequisites b53_common and dsa_core plus aforementioned
> file /etc/modules.
> 
> The installer should compare the content of
> /proc/device-tree/model
> to the string
> Lamobo R1
> 
> If this string is found, the file /etc/modules should be
> appended with b53_mdio on the installed system.

Hello,

I wonder why module autoloading doesn't work in this case.
All the modules you have listed as required:

- drivers/net/dsa/b53/b53_mdio.ko
- drivers/net/dsa/b53/b53_common.ko
- net/dsa/dsa_core.ko

are available (both in the installed system and in d-i).
The devicetree for the Lamobo R1 contains the following fragment:

  switch: ethernet-switch@1e {
          compatible = "brcm,bcm53125";
          [...]
  }

and the b43_mdio driver of_match table includes this
compatible:

static const struct of_device_id b53_of_match[] = {
        { .compatible = "brcm,bcm5325" },
        { .compatible = "brcm,bcm53115" },
        { .compatible = "brcm,bcm53125" },
        { .compatible = "brcm,bcm53128" },
        { .compatible = "brcm,bcm5365" },
        { .compatible = "brcm,bcm5395" },
        { .compatible = "brcm,bcm5397" },
        { .compatible = "brcm,bcm5398" },
        { /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, b53_of_match);

I would therefore expect that the module gets loaded automatically
without any manual intervention.  If it doesn't for some reason,
that sounds to me like something that we should try to address in
the kernel and not in d-i.  I'm reassigning the bug to the kernel
package to get input from the kernel maintainers on this.

Regards,
Karsten
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