[Lucid] (pre-stable) HID: handle joysticks with large number of buttons

[Stefan Bader]

Colin Ian King wrote:
> On Mon, 2010-02-22 at 15:21 +0100, Stefan Bader wrote:
>> BugLink: http://bugs.launchpad.net/bugs/492056
>>
>> Justification:
>>
>> Impact: Since fixing tablets to be _not_ detected as joysticks, joysticks
>> with a high number of buttons regressed to be detected as joysticks (due
>> to assigning themselves buttons beyond the range allowed for joysticks).
>>
>> Fix: Upstream changes (currently only in linux-next) add an overflow range
>> for that and start assigning from those buttons if there are more than 15
>> buttons.
>>
>> Testcase: Verified in the bug report with a Saitek X52. Regression should
>> not happen here as the additional range is only used for joystick devices
>> that have more than 15 buttons.
>>
>>
> Essentially lower buttons 0..15 are mapped as before onto
> BTN_JOYSTICK..BTN_JOYSTICK+15 (0x120..0x12f) and buttons above this are
> mapped to 0x2c0..0x2e7.  
> 
> Just a niggling question: Should there be any protection to stop buttons
> 41+ being mapped out of the BTN_TRIGGER_HAPPY range 0x2e8 upwards?
> 
> Colin
> 
Maybe there should. OTOH that range is at the end of the buttons/keys list. I
guess worst case it assigns buttons you cannot use as they are beyond the last
usable number.

Stefan