Re: [PATCH] Platform: samsung-laptop: add DMI information for SamsungN150 Plus

[Richard Schütz]

Am 29.12.2011 11:23, schrieb Corentin Chary:
> On 12/26/2011 11:22 AM, David Herrmann wrote:
> > On Mon, Dec 26, 2011 at 10:49 AM, Corentin Chary
> > <corentin.chary@xxxxxxxxx> wrote:
> > > On Sat, Dec 24, 2011 at 3:28 PM, David Herrmann
> > > <dh.herrmann@xxxxxxxxxxxxxx> wrote:
> > > > On Sat, Dec 24, 2011 at 3:20 PM, Matthew
> > > > Garrett<mjg59@xxxxxxxxxxxxx> wrote:
> > > > > On Sat, Dec 24, 2011 at 02:12:57PM +0000, Andrzej Prochyra wrote:
> > > > > > 'acpi_video0' not functional. Brightness can be controlled through
> > > > > > intel_backlight interface. There are 21 brightness levels and the
> > > > > > backlight can be turned off.
> > > > >
> > > > > If acpi_video0 doesn't work then we either need to work out why
> > > > > it's not
> > > > > working or make it vanish completely, so this patch isn't the correct
> > > > > approach.
> > > >
> > > > Just to make clear, intel_backlight isn't working properly either. If
> > > > my laptop boots with backlight at 50% then intel_backlight will only
> > > > work in the range 0%-50% on my machine. If I use the samsung module to
> > > > set it to 100% then intel_backlight works correctly in the range
> > > > 0-100% until next reboot/suspend.

The same problem exists on my N145 Plus, too.

> > > > So I'd recommend staying with the samsung module and disabling the
> > > > acpi_backlight entirely. The samsung module is the only backlight
> > > > control which works properly.
> > >
> > > Can I take a look at the DSDT to see how it's broken ?
> > > If it's really not functional, then it should be added to the
> > > blacklist in video_detect.c
> >
> > Raw and disassembled dsdt is attached.
>
> Took a quick look but didn't find anything obvious. What happens exactly
> with acpi_video0 ?

Either Samsung's ACPI is totally broken [ACPI Warning: _BQC returned an 
invalid level (20110623/video-472)] or they just don't support backlight 
setting via ACPI at all. Therefore it's implemented in the SABI stuff. 
So every device that needs SABI should be blacklisted in video_detect.

--
Regards,
Richard Schütz
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/