responses below
Greg KH wrote:
On Thu, Jun 25, 2009 at 04:21:09PM -0700, jack craig wrote:
Greg KH wrote:
On Thu, Jun 25, 2009 at 11:12:29AM -0700, jack craig wrote:
I knew the 'Big Guns' wouldnt fail me! :)
Greg KH wrote:
On Thu, Jun 25, 2009 at 09:04:59AM -0700, jack craig wrote:
i have created the rule, ...
BUS=="usb", ATTRS{idVendor}=="1808", ATTRS{idProduct}=="5555", NAME="obdii", MODE="0666", SYMLINK+="obdii"
when i plug in my widget, sure enough, i get a /dev/obdii created with
my desired permissions so udev is ok (AFAIK).
It should be a symlink, right? What is the link pointing to?
well, as i expect it, /dev/obdii should get created on usb hotplug
event and evaporate when its unplugged.
Again, what is that link pointing to?
the intention was for it to point to the /dev/bus/usb/003/### where
the libusb is accessing the device. i am creating this rule for the
first time, it could easily be wrong, but it does create the
/dev/obdii as a standalone character device file with the proper
perms.
i tried this code with and w/o the symlink and it made no difference.
And again, what exactly is this device node, or link? What does:
ls -l /dev/obdii
show?
crw-rw-rw- 1 root root 251, 29 2009-06-26 07:02 /dev/obdii
and the node that libusb is using ...
crw-rw-r-- 1 root root 189, 257 2009-06-26 07:02 /dev/bus/usb/003/002
and lsusb's view of the world, ...
Bus 001 Device 004: ID 058f:6335 Alcor Micro Corp. SD/MMC Card Reader
Bus 001 Device 003: ID 13fe:1f00 Kingston Technology Company Inc. DataTraveler 2.0 4GB Flash Drive
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 005 Device 002: ID 0b05:b700 ASUSTek Computer, Inc.
Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 002: ID 1808:5555 Multiplex Engineering OBDII to USB Interface
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 002 Device 002: ID 046d:c526 Logitech, Inc.
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
the rule i am trying to make work, ...
BUS=="usb", ATTRS{idVendor}=="1808", ATTRS{idProduct}=="5555", NAME="obdii", MODE="0666"
note i removed the SYMLINK bit as that was a shot in the dark on my part thinking well,
maybe if i added the SYMLINK, it would link /dev/obdii to /dev/bus/usb/003/002, but that didnt work.
What is this device?
an obdII interface.
Does a kernel driver bind to it already?
yes, as i needed to use the libusb_detach_kernel_driver so i could access my device with libusb.
If so,
why are you trying to mess with libusb?
because i'd prefer not to write any kernel level driver code.
so, a bit of background, i used to work on the usb stack years ago while at sco.
i enjoyed that work and have gotten away from development over the years since.
i wanted to get back into the usb swing of things(they have changed a lot as well as matured).
i chose the libusb approach as i could write my stuff in userland code and
the libusb provided the initial device discovery so i could use libusb to get a handle to my unique widget.
i just need to do read/write of 8 byte packets so i dont see a real need to use the kernel driver if the userland
option works for my sync i/o usage. pls let me know if i am missing something there, i may well be.
i have been using sudo /myprog to run my code as the perms created on /dev/bus/usb/003/002 are only 660.
i want to fix that so i can get world accessible access to the obd interface and udev seems to be
creating my device node properly.
my perception of the remaining issue is to get /dev/obdii device node to be what i use as during enumeration,
sometimes its /dev/bus/usb/003/002, but sometimes /dev/bus/usb/003/004, etc.
does this provide enough additional information? if not, what else may i provide?
i am going to try the udevadm monitor later this am, but got a chore do to first.
thx, jackc...
you are going to need to provide more information...
thanks,
greg k-h
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jack craig
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