From: Richard Purdie <rpurdie@rpsys.net>
To: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br>,
Andrew Morton <akpm@linux-foundation.org>,
linux-acpi@vger.kernel.org, "Rafael J. Wysocki" <rjw@sisk.pl>
Subject: Re: brightness control on thinkpad t61p
Date: Tue, 08 Jan 2008 16:29:31 +0000 [thread overview]
Message-ID: <1199809771.6053.42.camel@localhost.localdomain> (raw)
In-Reply-To: <20080108155401.GA4954@srcf.ucam.org>
On Tue, 2008-01-08 at 15:54 +0000, Matthew Garrett wrote:
> On Tue, Jan 08, 2008 at 03:45:02PM +0000, Richard Purdie wrote:
>
> > I did't get enough context above but I went through the archives and it
> > seems this is about linearising backlight values.
>
> Indeed. The ACPI spec provides a range of 0-100, without specifying what
> this actually means (it gives brightness and power consumption as two
> different examples). Implementations are only required to support a
> subset of these, with the others being ignored. The current hook into
> the backlight class exports this range but provides no means for an
> application to determine which values are valid - I'd prefer to just
> flatten the range to remove the holes. Given the lack of standardisation
> in the real meaning of the values, I don't think exporting the 0-100
> range buys us anything.
I agree with that. 0-100 actually breaks a useful and valid way the
class gets used in the "brightness + 1" case...
Cheers,
Richard
next prev parent reply other threads:[~2008-01-08 16:29 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-23 8:00 brightness control on thinkpad t61p Andrew Morton
2007-12-23 12:16 ` Rafael J. Wysocki
2007-12-24 7:34 ` Matthew Garrett
2007-12-24 17:14 ` Henrique de Moraes Holschuh
2007-12-26 22:10 ` Andrew Morton
2007-12-26 22:23 ` Matthew Garrett
2007-12-27 12:33 ` Henrique de Moraes Holschuh
2008-01-07 1:36 ` Henrique de Moraes Holschuh
2008-01-07 19:48 ` Matthew Garrett
2008-01-08 0:32 ` Henrique de Moraes Holschuh
2008-01-08 0:45 ` Matthew Garrett
2008-01-08 12:06 ` Henrique de Moraes Holschuh
2008-01-08 12:18 ` Matthew Garrett
2008-01-08 12:48 ` Henrique de Moraes Holschuh
2008-01-08 15:17 ` Matthew Garrett
2008-01-08 15:45 ` Richard Purdie
2008-01-08 15:54 ` Matthew Garrett
2008-01-08 16:29 ` Richard Purdie [this message]
2008-01-08 16:49 ` Henrique de Moraes Holschuh
2008-01-08 16:56 ` Richard Purdie
2008-01-08 17:36 ` Henrique de Moraes Holschuh
2007-12-27 12:31 ` Henrique de Moraes Holschuh
2007-12-24 17:08 ` Henrique de Moraes Holschuh
2007-12-26 22:10 ` Andrew Morton
2007-12-27 13:15 ` Henrique de Moraes Holschuh
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