Re: [PATCH 1/7 v3] HID: magicmouse: don't allow hidinput to initialize the device

[Jiri Slaby <jirislaby@gmail.com>]

On 09/02/2010 01:57 AM, Michael Poole wrote:
> Jiri Slaby wrote:
>> This looks weird. Is there any past discussion about why you cannot use
>> hidinput and you have to do all the input bits yourself while cheating
>> this very weird way?
> 
> The Magic Mouse and Magic Trackpad do not publish HID descriptors for
> the multitouch reports.  Given the variable-length report packets --
> and especially the Magic Trackpad's new, mutant DOUBLE_REPORT_ID
> packets -- it would be non-trivial to write accurate descriptors that
> the HID core can use.  (Someone wrote a patch to try that a few months
> ago.  It ended up adding significantly more lines to hid-magicmouse.c
> than it removed, and it was not obvious to me that it got the Report
> Count fields correct.)

Ok, makes sense. The proper solution is to call a driver hook in
hidinput_connect to do the mapping instead of report parsing done there,
right? (And not setting [gs]etkeycode in that case.)

Then the part of magicmouse_setup_input starting at the first __set_bit
will be exactly the hook.

Otherwise this hack looks like a hard cross-layer breakage.

/me wonders how HID issuers are creative in breaking standards.

regards,
-- 
js