Re: Commit 7751ab8e600f26e10c2ba12a92d48a4852a51da8

[Matthew Garrett <mjg59@srcf.ucam.org>]

On Wed, Apr 13, 2011 at 06:50:34PM +0200, Marco Chiappero wrote:

> I agree. The DSDT of any ALS equipped Vaio provides us 9 backlight
> levels (that are LCD/model specific), so the first and the last ones
> define our useful operating range, which is always different from
> 0-255 (eg. 13-255 for the Vaio S, 52-255 for the Vaio F, 7-182 for
> the Vaio Z, 7-213 for the Vaio TT and so on). However the code to
> retrieve and use those lower and upper bounds is still lacking
> upstream (I, Javier Achirica and many other people are testing a
> heavily modified sony-laptop.c written by us which includes lots of
> features that we might include soon, but there is no patchset yet).
> Moreover it is questionable whether to expose this "wire-range"/fine
> grain backlight device, which is intended to be used for an ambient
> light based regulation (that requires smooth transitions and
> sometimes minimal changes), while for normal backlight operations
> the 9 levels already mentioned should suffice.

Can this code be merged within the next week? If not I agree that it'd 
be better to drop this patch for now. I think exposing the full range of 
(usable) brightness values makes sense, since ALS policy is likely to be 
determined in userspace - we'll need some way to expose the appropriate 
mapping, but that's something that needs to be handled generically in 
the long run.

-- 
Matthew Garrett | mjg59@srcf.ucam.org