Talk:Udev

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Revision as of 13:47, 3 September 2012 by Sambul13 (Talk | contribs) (remove the "automounting usb devices" udev rules ?)

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usbtiny extra udev rule?

In the udev rules for usbtiny, there are 2 rules listed. Howver, adding the second one to my udev rules resulted in me not an "rc=-1" communication error when I tried to use my usbtiny. When I commented out this rule:

"SBSYSTEMS=="usb", ATTRS{idVendor}=="16c0", ATTRS{idProduct}=="0479", GROUP="users", MODE="0666"

everything worked fine. Not sure what the root of the issue is, but this rule makes the usbtiny programer unusable.

umask fails to apply to vfat/ntfs partitions

Has anyone else found that umask settings do not apply as they should? Setting umask to 002 or 0002 results in all files having the executable bit enabled. However, if I manually set the fmask/dmask values (ex: fmask=113,dmask=002) it works fine. --thayer 16:40, 5 May 2010 (EDT)

Possible to Auto Mount Optical Discs?

Is there a way to auto mount CD and DVDs with Udev? --Matthewbauer 23:12, 30 May 2010 (EDT)

I think I hacked up a way and added to the page. --Matthewbauer 00:16, 31 May 2010 (EDT)
With that rule udev will take a lot longer to "process events" during boot. (+-10s more than without it) --Vieira 02:20, 26 June 2010 (GMT)

Wrong command

It's not really wrong, just uselessly complex.

udevadm info -a -p $(udevadm info -q path -n [device name])

we are querying a path-based info, passing as parameter a name-based info query. We can obtain the same results with this much more rational command

udevadm info -a -n [device name]

This is not the only place in the web where I found this strange thing. :/ --4javier 07:14, 24 September 2010 (EDT)

Obsolete information?

Today (Dec 5 2010) I've been following the instruction in the wiki, I've found that udiskie isn't required to autoload CDs/DVSs without HAL, udisks works perfectly without it... only need to explicitly add dbus daemon loading to my rc.conf --RkG 02:42, 5 December 2010 (EST)

are you using a DE? udiskie is intended for people without one thestinger 02:54, 5 December 2010 (EST)
I'm using just a window manager (Xmonad, init-3 level), but installed Gnome also for other members of my family. But really I'm not in a Gnome session :-? --RkG 00:59, 6 December 2010 (EST)
do you use a file manager? pcmanfm and nautilus will both use udev and mount the disks automatically thestinger 13:47, 6 December 2010 (EST)
Yes, I'm using pcmanfm... maybe this should be reflected in the wiki as is a very easy option to control removable devices, inside xorg and with any window manager without having to mess with udev rules. Additionally I spawn a command at the begin of my sessions to automount a external 3.5' USB drive permanently plugged to my computer (udisks --mount /dev/sdXX) This "automount" integrates well with pcmanfm, and requires no additional utilities. (Also for pcmanfm compatibility, I need to start my session with "exec ck-launch-session dbus-launch --sh-syntax --exit-with-session $WM") --RkG 02:17, 7 December 2010 (EST)

SD cards don't cleanly umount

...because the rule as given creates a link: RUN+="/bin/ln -s /media/sd-%k /mnt/sd-%k" which is not deleted on removal. --Ideopath72 08:44, 18 December 2010 (EST)

How to match devices like /dev/sdb42

https://bbs.archlinux.org/viewtopic.php?pid=882211#p882211

I'm not and udev guru, but why sometimes it's

KERNEL!="sd[a-z][0-9]"

and in other examples

KERNEL!="sd[a-z]*"

?

Why not put

KERNEL!="sd[a-z][0-9]*"

everywhere?

Karol 10:11, 23 January 2011 (EST)

Some devices do not have any partitions, so you also want to match /dev/sdb for example that contains the filesystem in such a case. KERNEL!="sd[a-z]*" is the only expression that works for these ones. Xduugu 09:24, 5 February 2011 (EST)
I actually have such device - it's one of my mp3 players; the other one shows up as sdb1. I couldn't figure out how to make it work until I figured out it's not regexp (where '*' means 'zero or more', so "sd[a-z][0-9]*" would work even for 'sdb'), but a globbing pattern. Karol 09:49, 5 February 2011 (EST)
Hey, that is a very nice tip, thanks! We should incorporate this information in the article somehow, I tried to change the pattern like it were a regex, and was very puzzled it didn't work. -- Nic 11:22, 5 November 2011 (EDT)

Worth Mentioning?

In the section on how to prevent wireless and ethernet network devices from switching names would it be worth mentioning that the hardware addresses can also be obtained from ifconfig? It seems a slightly more obvious way of doing it to me.

net-tools (the package that provides ifconfig) was deprecated in favor of iproute2 so probably that's why it doesn't mention ifconfig.
Please sign the edits you make on the discussion pages. -- Karol 20:59, 15 July 2011 (EDT)
However, running:
$ ip addr
will also give you the MAC address (link/ether xx:xx:xx:xx:xx:xx) Axanon 16:40, 25 March 2012 (EDT)

remove the "automounting usb devices" udev rules ?

considering this discussion, I think the whole section should be removed. We shouldn't suggest to people to use this, there are Udisks Wrappers for this. Any objections? 65kid (talk) 11:06, 10 June 2012 (UTC)

+ 1 for me. Normal user should never touch these. However, you'd better leave a link or two about how to write udev rules manully. -- Fengchao (talk) 06:08, 12 June 2012 (UTC)
BTW: As of systemd 185-1, the deleted scripts were broken for NTFS partitions, yielding only "Transport endpoint is not connected". They still worked with classic initscripts, though. -- Misc (talk) 13:29, 20 June 2012 (UTC)
I'll disagree. udisks{1,2} needs PolKit, which I doubt is ever needed for normal setup and almost always is a PITA in configuration by itself. It is needed, though, for big and fat DE such as KDE, Gnome or even XFCE. But not for "home brew" environments. Neither who uses those big DE are going to write udev rules by themselves nor they are to install udisks and wrappers (as KDE, Gnome or XFCE brings their own automounting). As you removed the tips, you deprived those who wants their own setup of valuable information. The discussion you mention just reveals lack of the documentation and examples on UDev rules. ANd you propose just hide the KISS way and expose wrappers and bloatware of PolKit and UDisks. Lux (talk) 18:56, 27 July 2012 (UTC)
I'm with Lux. I spent a while searching for these rules and was sad to see them gone. Maybe a separate wiki page with a link from here? Jaredcasper (talk) 07:04, 30 July 2012 (UTC)
udev rules were never meant to be used for stuff like this, it was an ugly and broken hack. For example the umount rules didn't make any sense because the device was already gone when the rule matched, so there was nothing to unmount. And polkit/udisks is neither bloatware nor hard to configure. It is a single process running in the background and doesn't need any configuration whatsoever as long as you have a proper ConsoleKit session set up (but I guess ConsoleKit is bloatware too...). If you seriously think that these ugly and hacky udev rules are "more KISS" than udisks, I personally can't take you seriously, sorry. 65kid (talk) 09:41, 30 July 2012 (UTC)
I agree with Lux. Numerous users of Plug computers wouldn't install Udisks etc. And Udisks topic should be separated to a new article and only referenced by a link in this complex enough for a novice by itself Udev topic. Unmounting detached devices 'after the fact' in udev-automount rules does make sense to drop handles to now empty folders where they were mounted. If udev can't delete the folder, it remains shared by Samba and users with rw access to then mounted disk can write files to it, which then be replaced by content of a remounted drive. So its data loss threat to leave these folders accessible. Sambul13 09.40, 03 September 2012 (UTC)

Extract the UDisks into new article

As UDev is more generic than just disk mounting subsystem, I propose to extract the UDisks part into its own page to keep things simple and clear. Lux (talk) 19:32, 27 July 2012 (UTC)

Integrating article content with systemd

Despite udev was merged into systemd, which has border functionality, a single wiki article for systemd with udev features included would be very difficult to comprehend or follow in practice. Keep it simple, a separate wiki page per major systemd feature like udev and automount.