Re: [Libusb-devel] libusb 0.1 usb_detach_kernel_driver_np works only once

On Thu, 27 Nov 2008, Eberhard Fahle wrote:

Hi,
On Donnerstag, 27. November 2008 16:56:32 Alan Stern wrote:

quoted

On Thu, 27 Nov 2008, Eberhard Fahle wrote:

quoted

I'd sign that petiton for a user-editable "hid-quirks" file right away!

This is the second time I come along a HID-Device that is grabbed by the
hiddev/hidraw drivers without suppling the necessary tools to actually
use the device!
Current issue : Device is grabbed by hidraw, and you can't even check the
interface-number of the device you are looking at.

quoted

I don't understand this comment.  Do you mean that you can't tell which
underlying USB interface or device is associated with a particular
hidraw device file?

Right. In the hiddev-driver the device-info structure has everything one could 
possibly need to know:
struct hiddev_devinfo {
	__u32 bustype;
	__u32 busnum;
	__u32 devnum;
	__u32 ifnum;
	__s16 vendor;
	__s16 product;
	__s16 version;
	__u32 num_applications;
};
 
And for some reason I don't understand, this is what's exposed of the above by 
the hidraw driver (which keeps a struct hid_device internally and simply 
copies all the information from there):

struct hidraw_devinfo {
	__u32 bustype;
	__s16 vendor;
	__s16 product;
};

At least knowing the interface-number is essential I think

And hidraw has no ioctl to get a string-descriptor from the device (Serial-
Numbers are very common nowadays)

quoted

There's no point debating this sort of thing on the libusb-devel
mailing list.  

Yes.

quoted

If you're serious about it then you should post on the
linux-usb list, where the kernel developers will become aware of your
thoughts.  Better yet, instead of debating the issue, submit a patch!

I going to prepare for the hidraw driver since it basically works fine for my 
specific device. 

I still think it's worthwhile to bring this to the attention of the 
appropriate kernel developers.  In fact, I'll get the process started:

Dmitry, is there any way to accomplish what Eberhard wants to do?

Alan Stern

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