Re: [PATCH v3] Input: keyboard - add device tree bindings for simple key matrixes

On Tue, Jan 03, 2012 at 05:06:15PM +0000, Russell King - ARM Linux wrote:

On Tue, Jan 03, 2012 at 08:44:32AM -0800, Dmitry Torokhov wrote:

quoted

On Tue, Jan 03, 2012 at 04:29:30PM +0000, Russell King - ARM Linux wrote:

quoted

On Tue, Jan 03, 2012 at 08:22:21AM -0800, Simon Glass wrote:

quoted

Can the Linux key codes fit in 8 bits?

That depends on your point of view.

If you hack on X, then the answer is yes and you ignore the squeels of
your users when certain key presses get misinterpreted.  (The Psion LX
platform, otherwise known as the Netbook Pro, suffered with this problem.)

If you are a kernel hacker, the answer is no, because key codes currently
go all the way to 0x300.

For bootloader environment 0-255 range is probably sufficient though,
the upper keys are somewhat recent additions to the maps...

I assume you deem 'recent' to mean 8 years ago - they've been there since
at least 2.6.9, which is where the problem I refer to above was first
noticed.

Well, what's 8 years ;) On a more serious note keys above 255 are really
the extended set - keys of remote controls, camera control, touchpad,
various aplication launchers, etc that are not very interesting for
bootloader. But, as Olof mentioned, the encoding must be sufficient for
Linux as well as bootloader, so limiting it is not a good idea.

-- 
Dmitry