Re: Kernel 2.6.22-rc3 breaks USB: Unable to get HID descriptor(error sending control message: Operation not permitted)

[Kay Sievers]

On Sun, 2007-06-03 at 08:40 -0400, Justin Piszcz wrote: 
> On Sun, 3 Jun 2007, Kay Sievers wrote:
> 
> > On 6/3/07, Justin Piszcz <jpiszcz@xxxxxxxxxxxxxxx> wrote:
> >> On Sun, 3 Jun 2007, Jiri Kosina wrote:
> >> 
> >> > On Sun, 3 Jun 2007, Justin Piszcz wrote:
> >> >
> >> >>> Thanks. Does by any chance reverting the commit
> >> >>> 9f8b17e643fe6aa505629658445849397bda4e4f improve the situation?
> >> >> I have not played around with git/etc enough to back it out, if you have 
> >> a
> >> >> patch that applies on top of 2.6.22-rc3 that backs it out I can give it 
> >> a try.
> >> >
> >> > Please try this
> >> 
> >> [[ .. snip .. ]]
> >> 
> >> The patch was successful and now my USB device is working again!
> >
> > Please set:
> > CONFIG_USB_DEVICE_CLASS=y
> > there should be no patch needed. The option already defaults to yes in
> > the latest kernel.

> USB device class-devices (DEPRECATED) (USB_DEVICE_CLASS) [N/y/?] (NEW) y
> 
> Why is it deprecated if (nut/usb/etc fails) when its not used?  Does nut 
> or udev have to play catch-up to adhere to the new kernel changes?

The usb_device class was created to replace the /proc usbfs device nodes
which can't handle access-control-lists for logged-in users.
The device nodes worked fine, but plugging into the device events to
trigger userspace device handling created a bunch of problems with the
event timing. We have several open bugs, that can't be fixed properly
with using the usb_device-devices.

We changed the driver core to allow us to export device nodes directly
by bus-devices, instead of forcing us to create artificial devices like
the usb_device-class, just to export device nodes to userspace. If
systems set CONFIG_USB_DEVICE_CLASS=n (which defaults to yes now), one
new udev rule is needed, to replace the functionality of the
usb_device-class devices. Also the next version of HAL (which is where
nut receives the events from) will depend on the new device nodes, and
will not longer use usb_device devices. No changes to nut should be
needed.

Thanks,
Kay

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