Re: [PATCH] pch_gbe: Use a randomly generated MAC instead of failing probe

On 01/16/2012 04:31 AM, Alan Cox wrote:

quoted

Saving MAC address into external ROM is generic method, I think.
Though I know the ROM-less system using eg20t-pch, however I think
this system is not common.
So, I think pch_gbe shouldn't have auto-mac address assignment.

The problem is the module load fails for those cases. You cannot load
the module and use the standard ifconfig eth0 hw aa:bb:cc:dd:ee:ff
interface. The better fix might be to make sure it loads.

So change from

        memcpy(netdev->dev_addr, adapter->hw.mac.addr,
        netdev->addr_len);   
        if (!is_valid_ether_addr(netdev->dev_addr)) {
                dev_err(&pdev->dev, "Invalid MAC Address\n");
                ret = -EIO; 
                goto err_free_adapter;
        }

to just printing a warning, and check the current address when a user
tries to ifconfig it up and refuse to allow the port to go active.

I can go this route I suppose. I don't really understand the objection
to the use of a random mac addr in the special case given the prevalence
of this approach within existing drivers.

One reason I don't care for this alternative approach is that this
particular hardware is targeted at embedded use where we can't assume a
full init system is available, etc. It can be made to work of course, it
just isn't as automated.

David, would you orefer/accept an alternative patch which allows the
driver to load without a MAC address so the user can set it via ifconfig
after boot?

-- 
Darren Hart
Intel Open Source Technology Center
Yocto Project - Linux Kernel