[trusty] ACPI / video: Change the default for video.use_native_backlight to 1

[Yidi Lin]

After checking upstream commit logs, several patches are needed for
use_native_backlight=1.
But it does not guarantee that the patches work for every model.
It seems that adding a quirk for Dell Inspiron 5737 is much safer.
I will take Seth's suggestion.
Thanks.

On Wed, Jun 18, 2014 at 8:37 PM, Seth Forshee
<seth.forshee at canonical.com> wrote:
> On Wed, Jun 18, 2014 at 10:21:31AM +0800, Yidi Lin wrote:
>> Thanks for reminding.
>>
>> I will check what patches are necessary when use_native_backlight=1 is in use.
>
> Your other option is a sauce patch to add this machine to the dmi list
> in acpi_video.c. I think this is the safer option to avoid regressions
> with other hardware in 3.13. They've been working on these backlight
> issues for a long time because the solutions kept causing regressions on
> various machines, so I'm going to remain skeptical that they've really
> eliminated all the regressions until the changes have been upstream for
> quite a bit longer.
>
> Seth
>
>>
>> On Tue, Jun 17, 2014 at 7:40 PM, Tim Gardner <tim.gardner at canonical.com> wrote:
>> > On 06/16/2014 10:55 PM, Yidi Lin wrote:
>> >> BugLink: https://bugs.launchpad.net/bugs/1250401
>> >>
>> >> This patch is committed in v3.16-rc1 which fixes win8 backlight issue.
>> >> I had verified this patch for bug #1250401.
>> >>
>> >> This patch also fixes bug #1284030.
>> >>
>> >> commit 751109aad5834375ca9ed0dcfcd85a00cbf872b5
>> >> Author: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
>> >> Date:   Thu Jun 5 22:47:35 2014 +0200
>> >>
>> >>     ACPI / video: Change the default for video.use_native_backlight to 1
>> >>
>> >>     Now that we're hoping to have resolved all of the problems with
>> >>     video.use_native_backlight=1, make that the default at last.
>> >>
>> >>     Link: http://marc.info/?l=linux-acpi&m=139716088401106&w=2
>> >>     Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>
>> >>
>> >
>> > While this patch may fix back light issues for a Dell Inspiron 5737, how
>> > do you know changing the default won't break other platforms ? I imagine
>> > there was a bit of work that went into back light support between 3.13
>> > and 3.16-rc1, so I'm not sure flipping the default in 3.13 is sufficient.
>> >
>> > rtg
>> > --
>> > Tim Gardner tim.gardner at canonical.com
>>
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