linux-kernel - Re: r8169: MAC address programmed by coreboot to onboard RTL8111F does not persist

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Message-ID: <065dabff-dfcc-4a86-ba0e-e3d6de2d21fc@gmail.com>
Date: Sat, 22 Mar 2025 14:04:59 +0100
From: Heiner Kallweit <hkallweit1@...il.com>
To: Paul Menzel <pmenzel@...gen.mpg.de>, nic_swsd@...ltek.com
Cc: netdev@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
 Keith Hui <buurin@...il.com>
Subject: Re: r8169: MAC address programmed by coreboot to onboard RTL8111F
 does not persist

On 22.03.2025 09:50, Paul Menzel wrote:
> Dear Linux folks,
> 
> 
> Keith Hui reported the issue *MAC address programmed by coreboot to onboard RTL8111F does not persist* [1] below when using coreboot:
> 
Why do you consider this a bug? IOW: Where is it specified otherwise?

>> I am producing a coreboot port on Asus P8Z77-V LE PLUS on which this
>> issue is observed. It has a RTL8111F ethernet controller without
>> EEPROM for vital product data.
>>
>> I enabled the rtl8168 driver in coreboot so I can configure the LEDs
>> and MAC address. Lights work great, but the MAC address always
>> revert to 00:00:00:00:00:05 by the Linux r8169 kernel module. I
>> would then have to reassign its proper MAC address using ip link
>> change eno0 address <mac>.
>>
r8169 in a first place reads the factory-programmed MAC from the chip.
If this is 00:00:00:00:00:05, then this seems to be an issue with your
board.

>> The device appears to be taking the address I programmed, but r8169
>> reverts it both on init and teardown, insisting that
>> 00:00:00:00:00:05 is its permanent MAC address.
>>
>> Survival of coreboot programmed MAC address before r8169 driver is
>> confirmed by a debug read back I inserted in the coreboot rtl81xx
>> driver, as well as by temporarily blacklisting r8169.
>>
>> Vendor firmware is unaffected.
> 
What do you mean with this? What vendor firmware are you referring to?

> Do you have an idea, where in the Linux driver that happens?
> 
See rtl_init_mac_address() in r8169, and rtl8168_get_mac_address()
in Realtek's r8168 driver.

> 
> Kind regards,
> 
> Paul
> 
> 
> [1]: https://ticket.coreboot.org/issues/579#change-2029