Date: Tue, 12 Jul 2011 18:21:56 +0300 From: Andriy Gapon <avg@FreeBSD.org> To: Vitaly Magerya <vmagerya@gmail.com> Cc: freebsd-acpi@FreeBSD.org Subject: Re: (Missing) brightness controls of an Atom N455-based netbook Message-ID: <4E1C6694.6050706@FreeBSD.org> In-Reply-To: <CAL409KwHccndSa_venYqMdteJd7x3WFv5rgo6KxJ=N%2Bvtow1Nw@mail.gmail.com> References: <CAL409KwHccndSa_venYqMdteJd7x3WFv5rgo6KxJ=N%2Bvtow1Nw@mail.gmail.com>
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on 11/07/2011 19:08 Vitaly Magerya said the following: > Andriy Gapon <avg@freebsd.org> wrote: >>> From what I heard this isn't a problem with FreeBSD ACPI code, it's >>> a problem with Samsung firmware. AFAIK to get brightness controls >>> working on Windows you need to setup Samsung software that uses >>> undocument BIOS interface for it's function. >>> >>> Linux has what appears to be a reverse-engineered driver [1] that >>> does the same. Someone (probably me) needs to port it. >> >> Maybe, maybe not... Can you please verify which driver Linux actually uses on >> your system? > > Nothing but generic ACPI; samsung-laptop dirver is not used because > it doesn't white-list my laptop model (and for some reason fails > to attach when I load it with force=1, even though my BIOS definitely > has the signatures it is looking for). > > At any rate, brightness controls don't work under Linux. I officially give up on this case then :-) Maybe you'd want to report this problem to Linux folks too. If they come up with a fix we may borrow it from them. >> So I can see how this behavior can easily confuse our acpi_video driver. >> I see that Linux acpi video driver has some quirks in it, but not sure if it is >> able to handle this kind of issues. I would doubt that. >> >> Maybe you would feel adventurous enough to experiment with hacking your DSDT some >> more. For a start I would just try to remove that level % 10 == 0 check. > > Sure. I removed those checks, but there isn't much difference. > Here's a sample transcript: > > # sysctl hw.acpi.video > hw.acpi.video.crt0.active: 0 > hw.acpi.video.lcd0.active: 0 > hw.acpi.video.lcd0.brightness: 5 > hw.acpi.video.lcd0.fullpower: 100 > hw.acpi.video.lcd0.ecoomy: 5 > hw.acpi.video.lcd0.levels: 100 5 15 24 30 45 60 80 > hw.acpi.video.ext0.active: 0 > hw.acpi.video.out0.active: 0 > # sysctl hw.acpi.video.lcd0.brightness=45 > hw.acpi.video.lcd0.brightness: 5 -> 45 > # sysctl hw.acpi.video.lcd0.brightness=100 > hw.acpi.video.lcd0.brightness: 45 -> 100 > > No brightness changes actually occur during this. -- Andriy Gapon
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