Re: Andrew Lunn

[Andrew Lunn <andrew@lunn.ch>]

On Mon, Oct 27, 2025 at 10:51:39AM +0100, Paul SAGE wrote:
> The tg3 currently call eth_platform_get_mac_address to retrieve the
> MAC address from the device tree before trying the mailbox,
> NVRAM and MAC registers.
> However, this function only retrieves the MAC address from the device
> tree using of_get_mac_address.
> 
> We are using device_get_mac_address, which use fwnode to obtain a MAC
> address using the ACPI, so as we understand fwnode is an
> abstraction layer for both the device tree (on ARM) and ACPI (on x86)
> 
> If true, it could be appropriate to replace the call to replace
> eth_platform_get_mac_address with device_get_mac_address. This would
> avoid running the entire function only to later check for a dummy
> address.
> 
> Do you see any regression possible with this change ?

I don't know ACPI too well, DT is more advanced, and i tend to keep to
ARM platforms.

Does ACPI actually have a standardised mechanism for storing MAC
address? Is there anything in the standard?

If you do make use of device_get_mac_address(), how is the MAC address
stored in ACPI?

Documentation/firmware-guide/acpi/dsd/phy.rst says:

  These properties are defined in accordance with the "Device
  Properties UUID For _DSD" [dsd-guide] document and the
  daffd814-6eba-4d8c-8a91-bc9bbf4aa301 UUID must be used in the Device
  Data Descriptors containing them.

Is that what you are doing?

Have you looked through other MAC drivers? Are there any others
getting the MAC address from ACPI? Is it all proprietary, or is there
some standardisation?

If you do decide ACPI is missing this, and you want to move forward,
please also add a document under Documentation/firmware-guide/acpi/dsd
describing it.

	Andrew