board identification in /sys

board identification in /sys

[Andres Salomon]

I've been paying partial attention to the following thread:
http://marc.info/?l=linux-hotplug&m=131352330625733&w=2

It's an interesting discussion.  I realize that
moving /proc/device-tree to /sys would probably violate
sysrq-rules.txt, but it would be nice to have a common way to
represent things like cpu type, board id, etc in /sys that is populated
from the DT.  I haven't seen that discussed here yet, has anyone
considered it?

Re: board identification in /sys

[David Gibson]

On Thu, Aug 18, 2011 at 12:15:30PM -0700, Andres Salomon wrote:
> I've been paying partial attention to the following thread:
> http://marc.info/?l=linux-hotplug&m=131352330625733&w=2
> 
> It's an interesting discussion.  I realize that
> moving /proc/device-tree to /sys would probably violate
> sysrq-rules.txt, but it would be nice to have a common way to
> represent things like cpu type, board id, etc in /sys that is populated
> from the DT.  I haven't seen that discussed here yet, has anyone
> considered it?

Seems like a specious argument to me.  Despite all the problems of
/proc, the contents of /proc/device-tree are perfectly well-defined.
Or at least, its problems are entirely its own and not related to the
general problems of /proc.  The only argument here seems to be that
it's in /proc, and that's dealt with if that helper script just thinks
of /proc/device-tree as one possible place for the device tree path.
In the future it could be under /sys.  Indeed on sparc I think their
device tree representation is a separate filesystem and could be
anywhere.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

Re: board identification in /sys

[Andres Salomon]

On Fri, 19 Aug 2011 12:23:06 +1000
David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org> wrote:

> On Thu, Aug 18, 2011 at 12:15:30PM -0700, Andres Salomon wrote:
> > I've been paying partial attention to the following thread:
> > http://marc.info/?l=linux-hotplug&m=131352330625733&w=2
> > 
> > It's an interesting discussion.  I realize that
> > moving /proc/device-tree to /sys would probably violate
> > sysrq-rules.txt, but it would be nice to have a common way to
> > represent things like cpu type, board id, etc in /sys that is
> > populated from the DT.  I haven't seen that discussed here yet, has
> > anyone considered it?
> 
> Seems like a specious argument to me.  Despite all the problems of
> /proc, the contents of /proc/device-tree are perfectly well-defined.
> Or at least, its problems are entirely its own and not related to the
> general problems of /proc.  The only argument here seems to be that
> it's in /proc, and that's dealt with if that helper script just thinks
> of /proc/device-tree as one possible place for the device tree path.
> In the future it could be under /sys.  Indeed on sparc I think their
> device tree representation is a separate filesystem and could be
> anywhere.

Under sparc, it's typically in /openprom iirc.

I'd be fine with converting it to /sys/device-tree or some such thing
if that was okay with maintainers.