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Where is usb/devices file in Ubuntu 9.10?

2010 March 12

I am neither good developer nor good debuger, But since 9.10 upgradation / installation in my lab,  i could not find the usb/devices file in default path, which is:


And, it’s default path if you are on kernel 2.6.31 and usbfs is mounted by Init. Now, Ubuntu 9.10 is using upstart instead of init. It was working fine in Ubuntu 9.04. So it brought me in big world of usbfs. From Scott’s post usbfs: deprecate and hide option for !embedded. usbfs was enabled #417748 and disabled#488274 in Karmic Koala Released and Proposed version.

Ok, Ping back to original query, Ubuntu 9.10 is mounting debugfs instead of usbfs, regardless of  usbfs in enabled / disabled in Kernel. So you will fine usb/devices file under /sys/kernel/debug directory, check below output:

person@CANONICAL-DESK:/proc/bus$ mount
/dev/sda6 on / type ext4 (rw,errors=remount-ro)
proc on /proc type proc (rw)
none on /sys type sysfs (rw,noexec,nosuid,nodev)
none on /sys/fs/fuse/connections type fusectl (rw)
none on /sys/kernel/debug type debugfs (rw)



person@CANONICAL-DESK:/proc/bus$ uname -a
Linux CANONICAL-DESK 2.6.31-20-generic #57-Ubuntu SMP Mon Feb 8 09:05:19 UTC 2010 i686 GNU/Linux
person@CANONICAL-DESK:/proc/bus$ cat /sys/kernel/debug/usb/devices

T:  Bus=03 Lev=01 Prnt=01 Port=01 Cnt=01 Dev#=  2 Spd=12  MxCh= 0
D:  Ver= 1.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs=  1
P:  Vendor=046d ProdID=0a12 Rev= 1.00
S:  Manufacturer=Logitech
S:  Product=Logitech Wireless Headset
C:* #Ifs= 4 Cfg#= 1 Atr=80 MxPwr=100mA
I:* If#= 0 Alt= 0 #EPs= 0 Cls=01(audio) Sub=01 Prot=00 Driver=snd-usb-audio
I:* If#= 1 Alt= 0 #EPs= 0 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 1 Alt= 1 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
E:  Ad=01(O) Atr=09(Isoc) MxPS= 288 Ivl=1ms
I:* If#= 2 Alt= 0 #EPs= 0 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
I:  If#= 2 Alt= 1 #EPs= 1 Cls=01(audio) Sub=02 Prot=00 Driver=snd-usb-audio
E:  Ad=82(I) Atr=05(Isoc) MxPS=  32 Ivl=1ms
I:* If#= 3 Alt= 0 #EPs= 1 Cls=03(HID  ) Sub=00 Prot=00 Driver=usbhid
E:  Ad=83(I) Atr=03(Int.) MxPS=   8 Ivl=10ms


Currently i am testing this on Ubuntu 10.04 (Lucid Lynx) Alpha 3, and behavior is almost same. But it contains  new version of usbutils, which has new shell script called “usb-devices”. It will give you connected USB buses with machine, regardless of where your usb/devices file is! and output is almost same. check below output

hardik@hardik-desktop:~$ uname -a
Linux hardik-desktop 2.6.32-16-generic-pae #25-Ubuntu SMP Tue Mar 9 18:03:39 UTC 2010 i686 GNU/Linux
hardik@hardik-desktop:~$ usb-devices

T:  Bus=01 Lev=02 Prnt=02 Port=04 Cnt=01 Dev#=  3 Spd=12  MxCh= 0
D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
P:  Vendor=046d ProdID=c52e Rev=15.00
S:  Manufacturer=Logitech
S:  Product=USB Receiver
C:  #Ifs= 2 Cfg#= 1 Atr=a0 MxPwr=98mA
I:  If#= 0 Alt= 0 #EPs= 1 Cls=03(HID  ) Sub=01 Prot=01 Driver=usbhid
I:  If#= 1 Alt= 0 #EPs= 1 Cls=03(HID  ) Sub=01 Prot=02 Driver=usbhid

This question  was asked by my  friend Mr.  Sunil and  it turns in to  blog :). That’s it for now…

4 Responses leave one →
  1. Rik Vugteveen permalink
    April 18, 2010

    Hmmm sounds like a same problem i have. Did you find a solution?

    Thanks in advance

  2. April 18, 2010

    @ Rik,

    I am not seeing any problem, i explained where it is! Are you looking for solution? Please explain in detail.

  3. douglas permalink
    April 27, 2010

    how I can create a fake usbfs ?
    I need this to get my virtualbox working correctly.

  4. October 5, 2010

    have you tried /sys/bus/usb/devices ???

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