Re: [PATCH v6] r8152: Add support for setting pass through MAC address on RTL8153-AD

On Tuesday 14 June 2016 18:40:17 Greg KH wrote:

On Tue, Jun 14, 2016 at 06:28:10PM +0200, Pali Rohár wrote:

quoted

On Saturday 11 June 2016 19:42:26 David Miller wrote:

quoted

From: Andrew Lunn <andrew@lunn.ch>
Date: Sat, 11 Jun 2016 17:39:21 +0200

quoted

What is still open is do we want to accept it at all? Do we
accept the concept of putting the same MAC address on multiple
interfaces at hotplug time? Do we trust BIOS vendors to not
keep changing DSDT property name, since it is not
standardised?

Do we want this at all should be decided by somebody more
senior then those passing comments on the code.

Indeed, I think the behavior of using the same MAC address on
multiple interfaces if we plug several of these in at once is not
good.

We shouldn't behave this way just because the Microsoft driver
does.

I agree, but in some cases it is night mare for local admins when
booting different OS cause changing MAC address on local network.

Another similar situation: Imagine that you have two USB network
cards and both have "burned" into their registers same MAC
address. If you connect both those USB network cards, linux kernel
bind appropriate driver which read MAC address for both those
cards. But those addresses are same. What will linux kernel do in
this case?

If you can find such a broken USB device, try it and see :)

What do you mean by broken USB device?

You have never seen two ethernet cards with same MAC addresses? Right I 
have not seen two USB, but there is non zero chance that could happen. 
Specially now when more and more people starts using USB network cards.

(hint, might be hard to find, I've never seen such a device before.)

I don't see how that pertains to this issue, sorry, how does broken
USB hardware compare to a working Dell device?

It is same, how to handle two network cards which tell us, that they 
have same MAC addresses.

-- 
Pali Rohár
pali.rohar@gmail.com