Subject: Re: sysfs question

From: Stephen Hemminger <[email-masked]>
Date: Thu, 12 Nov 2009 09:00:41 -0800

On Thu, 12 Nov 2009 11:39:41 +0100
Kurt Van Dijck <[email-masked]> wrote:

> Hi,
> 
> Within the socketcan project, we came into a situation that
> might benefit with input from the netdev mailing list.
> 
> The main issue is the policy to add sysfs properties in
> /sys/class/net/canX.
> 
> The reason for this is that cards (devices) with multiple network
> interfaces may require properties per network.
> 
> An obvious property would be the 'channel number of the card'. Other
> properties could be things like type of output circuitry, ..., rather
> hardware specific.
> 
> I see currently 3 options:
> 1) such properties in /sys/class/net/canX would be allowed.
> 2) such properties would belong in /sys/class/net/canX/<subdirectory tbd>/
> 3) such properties would go somewhere else.
> 
> Some input with regard to sysfs policies would be helpfull.
> 
> Kurt

It sounds like the property you are proposing is a property of the
upper network layer not the hardware. Putting more properties in sysfs
is good if is hardware related, but awkward if it is really a protocol
attribute.