Subject: Ethernet Briding broken on APM Mustang on v4.0-rc1

From: [email-masked] (Mark Langsdorf)
Date: Wed, 25 Feb 2015 07:55:44 -0600

On 02/25/2015 07:45 AM, Christoffer Dall wrote:
> Update, apologies for noise,
>
> On Wed, Feb 25, 2015 at 01:41:01PM +0100, Christoffer Dall wrote:
>> Hi,
>>
>> Configuring bridged networking on the APM Mustang platform doesn't work
>> on v4.0-rc1.  It works fine on v3.19-rc1.
>>
>> When adding the interface to the bridge I get this error:
>>
>> can't add eth0 to bridge br0: Invalid argument
>>
>> Has anyone else seen this?
>>
>> Other ARMv8 platforms don't seem to be affected by this.
>>
>
> It seems that on v4.0-rc1 the APM ethernet card no longer gets a mac
> address (or rather, it gets 00:00:00:00:...) so assigning it an
> appropriate address naturally does the trick.
>
> I have no idea which change caused this behavior though.

Did you update your firmware recently? The MAC address is
stored as a UEFI shell variable and pushed into ACPI/DTB
by the firmware. At one point in the development history,
the symbol that held it changed from RGMII_MAC0 to MAC0.

You can reset it by going into the UEFI shell and running:
set MAC0 aa:bb:cc:dd:ee:ff
replacing aa:bb:cc:dd:ee:ff with the MAC address.

--Mark Langsdorf