Is there any way to reset USB devices?

Message

DeadlyMuffin · #1 Post by **DeadlyMuffin** » 2005-07-11 21:19

I'm using many USB devices spread accross several different USB hubs. Occasionally I have a hub drop off the network and need to reboot in order to get it to reconnect. Is there some command I can issue instead of rebooting the machine? The computer gets a lot of traffic and I need ot have it up as much as humanly possible.

dawgie · #2 Post by **dawgie** » 2005-07-12 21:45

I assume that you are using a 2.4 series kernel. When using the 2.6 kernel with Udev, sysfs, and hotplug, usb devices are much easier to use. You could configure your usb devices to automatically connect to the same device location when connected according to the device identification information. The should be no need to reboot.

One major problem with the 2.4 kernel and usb devices was the connection to device names.
EG: with the 2.4 kernel, I plug a usb card reader in and it is assigned name /dev/sda. If I unplug the device and plug it back in, sometimes it showed up as /dev/sdb.

-Bob

sensovision · #3 Post by **sensovision** » 2005-07-14 19:33

dawgie wrote: You could configure your usb devices to automatically connect to the same device location when connected according to the device identification information.
-Bob

Hi Bob, I suppose it could be done somehow but I'm not sure yet how... can you please tell the way or where to search on how to assign some letter for particular device? (I'm not using Udev but have hotplug)

dawgie · #4 Post by **dawgie** » 2005-07-14 20:20

sensovision wrote: Hi Bob, I suppose it could be done somehow but I'm not sure yet how... can you please tell the way or where to search on how to assign some letter for particular device? (I'm not using Udev but have hotplug)

There is a good "USB Flash Memory HOWTO" here:
http://www.tldp.org/HOWTO/Flash-Memory- ... x-2.6.html
UDEV is still fairly new and is still evolving. The system now has what is called "smart device naming" so that most USB devices automaticly have a logical name created when they are connected. Eventually, we may no longer need an fstab file.

-Bob

sensovision · #5 Post by **sensovision** » 2005-07-14 20:46

thaks Bob! I'll check it out now

DeadlyMuffin · #6 Post by **DeadlyMuffin** » 2005-07-18 18:11

I'm actually using a 2.6 kernel, it's just the generic 2.6 kernel I got through apt.

How can I use udev, sysfs, or hotplug to reload these devices?

dawgie · #7 Post by **dawgie** » 2005-07-18 18:23

DeadlyMuffin wrote:I'm actually using a 2.6 kernel, it's just the generic 2.6 kernel I got through apt.

How can I use udev, sysfs, or hotplug to reload these devices?

I did a UDEV how-to here:
http://forums.debian.net/viewtopic.php?t=259
Also you might want to add additional packages.
Try doing a:
#apt-cache search sysfs
and
# apt-cache search hotplug
to find some other related packages.

-Bob