Re: usbhid: Changes since 2.6.28 in quirk handling?

From: Jiri Kosina
Date: Wed Mar 18 2009 - 10:14:55 EST


On Fri, 13 Mar 2009, Bill Gribble wrote:

> Hi, I have been maintaining a patch for a quirky USB device built-in to
> a UMPC, the Raon Digital Everun. Without the patch, the builtin
> keyboard, mouse, and touchscreen are useless. I have never submitted it
> for inclusion in the kernel because there are less than 5 people who
> have ever even attempted to install Linux on this device, and it's
> discontinued. However, *I* use the thing daily, and its wifi device
> (libertas) has continued to get better support in the recent kernels so
> I port the patch forward.

Hi Bill,

we have drivers (and even whole architectures) supported by the kernel,
which have less than 5 users in the world, that's not a big deal.

It makes 5 people happy, and saves you the pain from having to keep the
out-of-tree code working with the Linux kernel API changing all the time.

> I noticed that the structure of the quirk handling code has changed
> somewhat; I left my patch using the "old" way of adding an entry to
> hid_blacklist in hid-quirks.c. Is there a document or email trail that
> describes the new way of structuring this quirk code? Any pitfalls to
> look out for?

Looking at your patch, the only thing you need is sending a special URB to
the device in order to make it operational, right?

Please look at hid-sony driver, which does exactly that for some of the
PS3 devices.

You then only need to add your device to hid_blacklist[], so that generic
driver doesn't get bound to it and it'd be driven by your special driver.

--
Jiri Kosina
SUSE Labs
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