Re: [RFC] usbnet: use eth%d name for known ethernet devices

From: Andy Green
Date: Thu Mar 24 2011 - 09:44:38 EST


On 03/24/2011 01:15 PM, Somebody in the thread at some point said:
The documentation for the USB ethernet devices suggests that
only some devices are supposed to use usb0 as the network interface
name instead of eth0. The logic used there, and documented in
Kconfig for CDC is that eth0 will be used when the mac address
is a globally assigned one, but usb0 is used for the locally
managed range that is typically used on point-to-point links.

Unfortunately, this has caused a lot of pain on the smsc95xx
device that is used on the popular pandaboard without an
EEPROM to store the MAC address, which causes the driver to
call random_ether_address().

Obviously, there should be a proper MAC addressed assigned to
the device, and discussions are ongoing about how to solve
this, but this patch at least makes sure that the default
interface naming gets a little saner and matches what the
user can expect based on the documentation, including for
new devices.

The approach taken here is to flag whether a device might be a
point-to-point link with the new FLAG_PTP setting in the usbnet
driver_info. A driver can set both FLAG_PTP and FLAG_ETHER if
it is not sure (e.g. cdc_ether), or just one of the two.
The usbnet framework only looks at the MAC address for device
naming if both flags are set, otherwise it trusts the flag.

Signed-off-by: Arnd Bergmann<arnd.bergmann@xxxxxxxxxx>
Cc: Andy Green<andy.green@xxxxxxxxxx>
Cc: patches@xxxxxxxxxx

For Panda case at least,

Tested-by: Andy Green <andy.green@xxxxxxxxxx>

-Andy
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