From: Matthew Garrett <mjg59@srcf.ucam.org>
To: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>,
linux-acpi <linux-acpi@vger.kernel.org>,
"trenn@suse.de" <trenn@suse.de>
Subject: Re: [PATCH] ACPI: disable the ACPI backlight control on laptops with buggy _BCL methods
Date: Fri, 9 Jan 2009 01:18:09 +0000 [thread overview]
Message-ID: <20090109011809.GA23213@srcf.ucam.org> (raw)
In-Reply-To: <1231463618.20746.93.camel@rzhang-dt>
On Fri, Jan 09, 2009 at 09:13:38AM +0800, Zhang Rui wrote:
>
> _BQC returns 3 when the actual backlight level is 0x50.
> We only know that the value returned by _BQC is invalid but we never
> know the value is an index until we see the _AML code.
If the value returned is less than the smallest value in the _BLC block,
then it's an index. This heuristic will never break a standards
compliant system, but (to the best of my knowledge) will work with any
of these systems that we're currently aware of.
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2009-01-09 1:18 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-08 2:58 [PATCH] ACPI: disable the ACPI backlight control on laptops with buggy _BCL methods Zhang Rui
2009-01-08 3:11 ` Zhang Rui
2009-01-08 3:32 ` Matthew Garrett
2009-01-08 6:32 ` Zhang Rui
2009-01-08 12:43 ` Matthew Garrett
2009-01-09 1:13 ` Zhang Rui
2009-01-09 1:18 ` Matthew Garrett [this message]
2009-01-09 1:53 ` Zhang Rui
2009-01-09 1:55 ` Matthew Garrett
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