linux-kernel - Re: [PATCH] Platform: samsung-laptop: add DMI information for Samsung N150 Plus

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Date:	Thu, 29 Dec 2011 12:49:41 +0100
From:	Corentin Chary <corentin.chary@...il.com>
To:	Richard Schütz <r.schtz@...nline.de>
Cc:	David Herrmann <dh.herrmann@...glemail.com>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	Andrzej Prochyra <andrzej@...chyra.name>,
	platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
	"Zhang, Rui" <rui.zhang@...el.com>
Subject: Re: [PATCH] Platform: samsung-laptop: add DMI information for Samsung
 N150 Plus

On Thu, Dec 29, 2011 at 12:45 PM, Richard Schütz <r.schtz@...nline.de> wrote:
> 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@...il.com> wrote:
>>>>
>>>> On Sat, Dec 24, 2011 at 3:28 PM, David Herrmann
>>>> <dh.herrmann@...glemail.com> wrote:
>>>>>
>>>>> On Sat, Dec 24, 2011 at 3:20 PM, Matthew
>>>>> Garrett<mjg59@...f.ucam.org> 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.

And that's ? Because new laptops that use SABI seems to have a working
acpi_video0.
Currently, N1{4,5}* seems to be affected.

-- 
Corentin Chary
http://xf.iksaif.net
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