Re: udev doesn't know about devices further up the tree.

[Simon Huggins <huggie@earth.li>]

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On Fri, Jun 16, 2006 at 10:35:33AM +0200, Kay Sievers wrote:
> On Fri, 2006-06-16 at 09:05 +0100, Simon Huggins wrote:
> > I wrote my first udev rule the other day.
> > It reads:
> > KERNEL=="sd*", PROGRAM="/home/huggie/bin/camera %k", SYMLINK+="%c"
> > where bin/camera does:
> > DEV=$1
> > DISK=`echo $DEV|sed -e 's/.*\(sd.\).*/\1/;'`
> > udevinfo -a -p /block/$DISK/$DEV|grep manuf|grep PENTAX >/dev/null 2>&1 && \
> >         echo camera && exit 0
> > i.e. basically if the usb device (or any device because I'm not that
> > fussy) above the block device is made by PENTAX then echo camera
> > otherwise I just echo $DEV back again.
> > But it strikes me as a bug that I have to spawn out of udevd to run
> > udevinfo in order to just name the device based on what it is.
> > Why aren't SYSFS attributes from higher up the device path available
> > somehow when writing rules?
> Adding a single SYSFS attribute:
>   SYSFS{vendor}=="PENTAX"
> or
>   SYSFS{manufacturer}=="PENTAX"

> should do it and will try to find the value on all devices up the chain,
> but you can't mix SYSFS, BUS or ID values from different devices.

Hmm, ok it's working now.  I must have fucked up the rule somehow
originally sorry for wasting your time.

Can I suggest that the part in
http://www.reactivated.net/writing_udev_rules.html
which says:

	This is to demonstrate that you generally can not mix-and-match
	attributes from different sections of the udevinfo output - your
	rule will not work. 

be reworded or removed then.  I'm not quite sure what it should say - I
just failed and then read more of the docs and came across this and
thought that what I was trying was never going to work.

I now have:
KERNEL=="sd*", SUBSYSTEM=="block", SYSFS{manufacturer}=="PENTAX",
SYMLINK+="camera"
which appears to work fine yet the block and the PENTAX are indeed in
different sections of the udevinfo output.

-- 
 ,--huggie-at-earth-dot-li--------stuff-thing-stuff----------DF5CE2B4--.
_|  "Don't worry, understanding of the topic being discussed has been  |_
 |          optional for a long time on debian-devel@." -- Md          |
 `- http://www.earth.li/~huggie/ - http://www.blackcatnetworks.co.uk/ -'

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