Re: udev rules for new firewire driver stack

[David Moore <dcm@MIT.EDU>]

On Wed, 2008-08-20 at 22:57 +0200, Stefan Richter wrote:
> David Moore wrote:
> > On Wed, 2008-08-20 at 21:39 +0200, Stefan Richter wrote:
> > 
> >> # Set GROUP="video" for some IEEE 1394 device types, driven by the new firewire stack.
> >> # We cannot use the GROUP directive because the significant device type attributes
> >> # live in child devices. So change the group after the fact with chgrp.
> >>
> >> # IIDC devices: industrial cameras and some webcams
> >> SUBSYSTEM="firewire", ATTR{specifier_id}="0x00a02d", ATTR{version}="0x00010?",\
> >>  PROGRAM="/bin/chgrp video /dev/%P"
> >>
> >> # AV/C devices: camcorders, set-top boxes, TV sets, various audio devices, and more
> >> SUBSYSTEM="firewire", ATTR{specifier_id}="0x00a02d", ATTR{version}="0x010001",\
> >>  PROGRAM="/bin/chgrp video /dev/%P"
> >>
> > 
> > I tried playing with rules like this about a year ago, but it didn't
> > work because the spec_id was only available in the child nodes of the
> > firewire device, so udev couldn't match on it (see more below).  Has
> > that changed so these work now?
> 
> This hasn't changed; hence I use chgrp on %P which is the parent.
> 
> I.e. these rules trigger on fwX.Y events but modify the (then already 
> existing) /dev/fwX file.
> 

Okay, I see.  The reason that didn't work on Fedora 7 was that a SYMLINK
rule can't use this %P trick since the target of the symlink can't be
overriden (at least to my knowledge).  And Fedora didn't like putting
chgrp commands directly in the udev rule since there was some PAM
console.perms magic elsewhere that dealt with the chgrping all in one
place based on filename.

Of course, for Fedora at least, all that is moot now since the PAM magic
is replaced with PolicyKit magic.  I'm not sure if other distributions
still use console.perms.

-David