Re: [PATCH can-next v6] can: add tx/rx LED trigger support

From: Kurt Van Dijck
Date: Tue Sep 04 2012 - 03:11:24 EST


On Mon, Sep 03, 2012 at 10:54:49PM +0200, Oliver Hartkopp wrote:
> On 03.09.2012 20:29, Fabio Baltieri wrote:
>
> > On Mon, Sep 03, 2012 at 08:13:35PM +0200, Kurt Van Dijck wrote:
> >> On Mon, Sep 03, 2012 at 02:40:39PM +0200, Marc Kleine-Budde wrote:
> >>> The net->ifindex is unique. But it's only an integer. Usually can0 has a
> >>> ifindex != 0, so a simple can%d is contra productive here.
> >>>
> >>> Some pointers to related code:
> >>> http://lxr.free-electrons.com/source/drivers/base/core.c#L1847
> >>> http://lxr.free-electrons.com/source/drivers/base/core.c#L73
> >>> http://lxr.free-electrons.com/source/include/linux/device.h#L695
> >>>
> >>> comments?
> >
> > That would probabily makes really hard to choose the right
> > default_trigger for led devices to get to the appropriate CAN LED in
> > embedded systems, as trigger name would depend from other network
> > devices and probing order (correct me if I'm wrong).
> >
> > Something with device name would probaily be more appropriate here.
> >
> >>
> >> a very recent idea: something with netdevice notifiers and NETDEV_CHANGENAME ...
> >> http://lxr.free-electrons.com/source/net/core/dev.c#L1030
> >>
> >> you could: rename the trigger, or if we think it's usefull,
> >> block the netdev rename when its triggers are in use.
> >
> > Blocking the rename looks overkill to me,

renaming a netdev _after_ first attaching led triggers looks stupid to me
anyway.

> > what about using device name
> > with an optional "port id" appended to it? Sounds simpler...
>
>
> The name of the device can only be changed when the interface is down.
> Is it possible to put some scripting around it to detach and attach the leds
> to the interfaces on ifup/ifdown triggers?

Are the led triggers available for using while the netdev is down then?

Kurt
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