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<== Date ==> <== Thread ==>

Subject: Re: Help with udev
From: "J. Lewis Muir" <jlmuir@anl.gov>
To: tech-talk@aps.anl.gov
Cc: "Scott D. Davilla" <davilla@4pi.com>, jennings@aps.anl.gov
Date: Wed, 02 Jan 2008 11:22:58 -0500
On 12/21/07 2:15 PM, Mark Rivers wrote:
> That is the good news. The bad news is that setting the permissions
> on that device, /dev/bus/usb/005/018 does not allow a non-privileged
> user to access the device. In order for a non-privileged use to
> access the device, I find that I need to set the permissions to 666
> on /proc/bus/usb/005/018 i.e. the /proc filesystem, not the /dev
> filesystem. If I change the permissions on the /proc filesystem
> manually then I can run the IOC in a non-privileged account.
>
> I am not a Linux expert by any means. What is the difference between
> the /dev and /proc filesystems? Peter also mentioned the /sys file
> system. How is that related?
>
> I am using the libusb library to access the device. With that API one
> simply calls usb_find_busses and usb_find_devices to locate the device
> you are interested in. You don't specify the file system anywhere.
>
> Any ideas how to get the permissions I need set on the device?
>
> Thanks, Mark

Hi, Mark.

Maybe the libusb library is using /proc/bus/usb as the virtual file system instead of /dev/bus/usb. What happens if you set the USB_DEVFS_PATH environment variable to "/dev/bus/usb" in the process environment of your IOC?

-lewis
Replies:
Re: Help with udev Emmanuel Mayssat
RE: Help with udev Mark Rivers

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