Re: regression since 2.6.36: backlight in sony-laptop not working

Dmitry Torokhov
2010-11-16T17:42:05Z

On Tue, Nov 16, 2010 at 11:18:50PM +0900, Mattia Dongili wrote:
> On Tue, Nov 16, 2010 at 02:16:42PM +0900, Norbert Preining wrote:
> > On Fr, 12 Nov 2010, Mattia Dongili wrote:
> > > You will need an updated input-kbd to set the scancode map.
> >
> > Ouch.
> >
> > > > Does that mean that 2.6.37rc is too new for the user space?
> > >
> > > Maybe. Anyway if evtest reacts positively to key presses then it's a
> > > userspace issue and not the driver's.
> >
> > What is strange that there *WAS* a change in the kernel that triggered
> > that. Old kernels still work fine. I just tried 2.6.36 and it was working.
> >
> > I always thought that kernel changes should not break user space
> > (well, without good reason).
>
> it's the same as this:
> https://bugzilla.kernel.org/show_bug.cgi?id=23022
>

Right, we up-revved evdev protocol version to reflect the fact that it
supports large scancodes but the procotocl is backwards-compatible and
older userspace should have no problems talking with evdev and do
remaps. For example, udev's keymap utility workds just fine here.
Unfortunately input-kbd insists on working with only one version of the
protocol instead if checking if the protocol "at least N". This shoudl
be fixed in input-kbd.

Thanks.

--
Dmitry