LinuxQuestions.org
Support LQ: Use code LQ3 and save $3 on Domain Registration
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Distributions > Slackware
User Name
Password
Slackware This Forum is for the discussion of Slackware Linux.

Notices

Reply
 
Search this Thread
Old 11-06-2010, 06:23 AM   #1
catkin
LQ 5k Club
 
Registered: Dec 2008
Location: Tamil Nadu, India
Distribution: Servers: Debian Squeeze and Wheezy. Desktop: Slackware64 14.0. Netbook: Slackware 13.37
Posts: 8,551
Blog Entries: 28

Rep: Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176
VirtualBox USB devices history effect: fstab and udev rules


Hello

Further to this LQ thread I have investigated further and found a persistent "history effect". AFAIK this is specific to Slackware hence posting in this sub-forum rather than in the Virtualization forum.

After a default installation (Slackware64 13.1 and VirtualBox 3.2.8 but has been seen with earlier versions) the VM's host window's Devices -> USB Devices list is greyed out.

The problem can readily be fixed by adding a usbfs line to fstab but it should not be necessary; udev should do the job. And udev does do the job if /etc/udev/rules.d/10-vboxdrv.rules is renamed as 91-vboxdrv.rules (that moves it to the end of the lexical ordering) and the fstab line is removed and the host is rebooted.

This solution suggests that some inter-action amongst the udev rules is causing the problem. The problem rule(s) could be identified by moving <nn>-vboxdrv.rules within the lexical ordering until shifting it just one position triggers the problem.

Now for the persistent history effect. After renaming to trigger failure (say 10-vboxdrv.rules) and then renaming to a previously working name (say 55-vboxdrv.rules) it still fails, even after reboot! The persistent history effect is removed by restoring the fstab line, rebooting, removing the fstab line and rebooting.

Simulating reboot effects by re-initialising udev rules (udevadm control --reload-rules), usbfs (forgot to umount, ran commands from rc.S to mount) and VirtualBox (/etc/rc.d/rc.vboxdrv restart) did not remove the history effect but a full reboot did.

I have no idea what file change(s) are storing the history effect.

Mostly I'm publishing this in case it helps anybody or in case someone can suggest ways of removing the history effect without rebooting. At the current rate of progress it's going to take a long time for me to home in on the problem rule and maybe find a fix.

Meanwhile there's an effective workaround.

Best

Charles
 
Old 11-07-2010, 01:34 AM   #2
mRgOBLIN
Slackware Contributor
 
Registered: Jun 2002
Location: New Zealand
Distribution: Slackware
Posts: 999

Rep: Reputation: 227Reputation: 227Reputation: 227
What about if you "umount usbfs" and comment out the block in rc.S that mounts it?

This works for me and I have no fstab entry for usbfs.
 
1 members found this post helpful.
Old 11-07-2010, 01:15 AM   #3
catkin
LQ 5k Club
 
Registered: Dec 2008
Location: Tamil Nadu, India
Distribution: Servers: Debian Squeeze and Wheezy. Desktop: Slackware64 14.0. Netbook: Slackware 13.37
Posts: 8,551
Blog Entries: 28

Original Poster
Rep: Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176
Quote:
Originally Posted by mRgOBLIN View Post
What about if you "umount usbfs" and comment out the block in rc.S that mounts it?

This works for me and I have no fstab entry for usbfs.
Thanks mRgOBLIN

Doesn't that cause any problems with USB devices that are used by the host? I'm not clear about what usbfs is and netsearching didn't find any explanations but AFAIK it's a virtual file system providing information about USB devices so removing the rc.S code that mounts it would prevent that information being made available ... only guessing

Either which way, I'll certainly try unmounting the usbfs when trying to re-initialise without a reboot (intended to do that before but overlooked).

The rc.S code suggests that the only effect of having the usual VirtualBox usbfs line in fstab is to set the usbfs group and permissions -- otherwise rc.S mounts usbfs at /proc/bus/usb anyway, with default group and permissions.

I'll experiment next time it stops working which will likely be soon -- I've just renamed to 39-vboxdrv.rules which is before 40-usb_modeswitch.rules (a likely culprit?) and close to the beginning of the ordering.
 
Old 11-07-2010, 09:48 AM   #4
catkin
LQ 5k Club
 
Registered: Dec 2008
Location: Tamil Nadu, India
Distribution: Servers: Debian Squeeze and Wheezy. Desktop: Slackware64 14.0. Netbook: Slackware 13.37
Posts: 8,551
Blog Entries: 28

Original Poster
Rep: Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176Reputation: 1176
It's working OK with 39-vboxdrv.rules so I'm going to have to leave it there for a while because previous tests didn't fail immediately.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Udev Rules To Differentiate Between Multiple Identical Devices mcalautti Linux - General 15 08-26-2010 09:12 AM
udev rules not unmounting usb jjinno Linux - General 2 11-24-2009 03:29 PM
USB flash disk read problems using udev rules janfranken Linux - Desktop 6 02-18-2009 06:33 PM
Udev rules and USB bus cferron Linux - Hardware 4 03-11-2008 09:37 AM
Plugging devices on USB does not give any effect (kernel 2.6.6) zby Linux - Hardware 1 07-22-2004 09:27 AM


All times are GMT -5. The time now is 08:32 AM.

Main Menu
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
identi.ca: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration