Date: Mon, 11 Jul 2011 19:08:06 +0300 From: Vitaly Magerya <vmagerya@gmail.com> To: Andriy Gapon <avg@freebsd.org> Cc: freebsd-acpi@freebsd.org Subject: (Missing) brightness controls of an Atom N455-based netbook Message-ID: <CAL409KwHccndSa_venYqMdteJd7x3WFv5rgo6KxJ=N%2Bvtow1Nw@mail.gmail.com>
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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. > 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.
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