Re: [linux-usb-devel] [RFC] HID bus design overview.

Dmitry Torokhov
2007-04-02T04:09:23Z

On Saturday 31 March 2007 18:49, Jiri Kosina wrote:
>
> Hi,
>
> in fact I am not entirely sure that the specialized drivers hooked to the
> HID bus should be passed individual fields/usages by the generic HID
> driver. That would imply that generic HID layer would have to parse the
> received report using information retrieved from the report descriptor of
> the device. But this is in some way in contrary to one of the features
> this effort should be heading to, isn't it? We want to provide means how
> to bypass possible errors in HID descriptor of the device (or do any other
> possible quirky handling) - we want to be able to allow for completely
> different interpretation of fields than the generic HID parser would do,
> right?
>
> So I guess the above should rather be
>
> static void my_driver_hid_report(struct hid_device *hid, u8 *data,
> int size)
> {
> if (special_processing_needed(data)) {
> do_special_processing(...);
> input_event(field->hidinput->input, XXX, YYY, ZZZ);
> ...
> } else
> hid_input_report(hid, data, size);
> }
>

Well, this of course is most flexible, however I think that for most
drivers hooking into parsed data would be much easier. That means that
we need to allow defining 2 hooks - one for raw data and another for
parsed reports and let drivers decice which one they want to use.

--
Dmitry