Re: [DOC] The documentation for HID Simple Driver Interface 0.5.0

Jiri Kosina
2007-03-06T13:47:43Z

On Mon, 5 Mar 2007, Marcel Holtmann wrote:

> no, because if I recall correctly these are the boot mode drivers and
> actually not used at all in any modern distribution.

That's correct.

> For me the task of converting HID reports into input events shouldn't be
> actually the job of the HID core layer. My understanding is that the HID
> core should support multiple transport layers. This is currently
> achieved through the hid_device abstraction and used by the USB and by
> the Bluetooth subsystem. This is the lower interface to HID. On the
> upper interface I like to see a driver like interface. So we can
> register specific drivers that can handle specific use cases or vendor
> specific reports.

This I completely agree with, and have this on my TODO for quite a long
time. If Li Yu would like to spend some time on it, it certainly would
help. The current "simple HID interrface" is a suitable workaround for
various buggy/broken/nonstandard hardware which is currently not handled
by the HID kernel code properly, but it's definitely not a long-term
solution that should go to mainline.

> For standard keyboard and mouse reports we however should have a
> standard driver that can handle most of them.

Unfortunately there is a non-trivial bunch of hardware that pretends to be
standard keyboard/mouse, but behaves badly. Last week I had to do
workaround for Logitech S510, which seems to generate usages far above the
logical maximum specified in report descriptor, to give one example.

So we will probably end up with many small driver for exotic pieces of
hardware being registered to the hid bus. But this is definitely much
better than the current mess of hid quirks.

On Mon, 5 Mar 2007, Dmitry Torokhov wrote:

> We are running out if quirks and we can't continue in this fashion so Li
> tried to provide mechanism to augment default HID behaviour for sepcific
> devices.

That's right. We could always extend the quirks so that it's long long, or
something like that, but this is also not sustainable in the long term.

--
Jiri Kosina