Re: [patch net-next-2.6 1/2] net: allow to change carrier via sysfs

Tue, Aug 30, 2011 at 08:25:53PM CEST, shemminger@vyatta.com wrote:

On Tue, 30 Aug 2011 20:11:37 +0200
Michał Mirosław [off-list ref] wrote:

quoted

2011/8/30 Jiri Pirko [off-list ref]:

quoted

Allow to write to "carrier" attribute. Devices may implement ndo_change_carrier
callback to allow changing carrier from userspace.

Do you expect drivers using implementation different than just calling
netif_carrier_on/off? Or is it supposed to also e.g. power down PHYs?

BTW, I like this feature!

Ok for virtual devices, but please don't implement it in real hardware.
There is already enough breakage in carrier management in applications.
It also overlaps with operstate perhaps that is a more more complete
solution.

Looking at operstate doc, I'm not sure what exactly do you mean by
"overlapping".

The main purpose of my patch is to give certain virt devices the
opportunity to emulate carrier loss. But I do not see reason why this
can't be implemented by real hw. Or course there should be explicitelly
documented the purpose of this feature.

Jirka