Hi,
i'm working on an PCIe device driver for an FPGA card from Xilinx. The computing environment is as follows:

% uname -a
Linux dev-2 2.6.32-131.0.15.el6.x86_64 #1 SMP Sat May 21 10:27:57 CDT 2011 x86_64 x86_64 x86_64 GNU/Linux

% cat /etc/redhat-release
Scientific Linux release 6.1 (Carbon)

When i tried to load the module, i ran into the following error:

----------------------------------------
% sudo insmod ./foo_main.ko
insmod: error inserting './foo_main.ko': -1 Device or resource busy
----------------------------------------

i don't know why i got this error message. foo does not appear in the lsmod output. It is not clear to me why the kernel thinks the device/resource is "busy". i also attempted the following to remove the device but to no avail:

% sudo echo "51ac 9041" > /sys/bus/pci/drivers/foo/remove_id
bash: remove_id: Permission denied

wherein 51ac and 9041 are the vendor and device IDs respectively.

My questions are:
* Did i misuse the "sudo echo ... remove_id" command (i do have sudo
privilege)? How did i end up getting this error message?
* What is the cause of the "Device or resource busy" error message
and how i can rectify the problem?

If this is not the right forum for question of this nature, i apologize, and please kindly point me in the right direction.

Thanks.

If you're writing the driver yourself, you should add a bunch of printk()'s to your code, and then trace the program flow with dmesg. This will help you to troubleshoot which part of your driver is failing.

Hi jhwilliams,
Thank you for your input.

> If you're writing the driver yourself, you should add a bunch
> of printk()'s to your code,

i did add a bunch of printk()'s in most functions including
static int __init foo_init(void)
and examined the output from both dmesg and /var/log/messages but i did not find additional clues other than error messages i included in my first posting. Moreover, i also checked the function return values whenever possible.