Re: [PATCH 0/4] drm/i915: backlight sysfs bl_power and brightness == 0

[Clint Taylor <clinton.a.taylor@intel.com>]

On 08/12/2014 07:11 AM, Jani Nikula wrote:
> This series adds support for backlight class sysfs bl_power attribute
> for eDP panels, which allows switching the backlight on/off. This is
> done using the eDP panel power control as a sub-state of everything else
> being enabled. Patch 4 also makes 0 brightness switch off the eDP
> backlight using the same mechanism. This is all eDP specific, with no
> support for LVDS.
>
> I'm not particularly fond of these patches, but there appears to be
> demand for them, particularly since
>
> commit 6dda730e55f412a6dfb181cae6784822ba463847
> Author: Jani Nikula <jani.nikula@intel.com>
> Date:   Tue Jun 24 18:27:40 2014 +0300
>
>      drm/i915: respect the VBT minimum backlight brightness
>
> All the discussions seem to just drag on and on without code to speak
> about, so here goes. I've tried to make this as simple and unintrusive
> as possible.
>
> BR,
> Jani.
>
I have hand merged the first 3 patches of this series into kernel 3.10 
Chromium and the bl_power sysfs entry is functional and turns off 
backlight power independent of the PWM as designed.

The fourth patch is non-functional due to the difference between the 11 
Chromium backlight patches from April 2014 and current upstream 
implementation.

Clint

>
> Jani Nikula (4):
>    drm/i915/dp: split up panel power control from backlight pwm control
>    drm/i915: add some framework for backlight bl_power support
>    drm/i915/dp: make backlight bl_power control power sequencer backlight
>    drm/i915: switch off backlight for backlight class 0 brightness
>
>   drivers/gpu/drm/i915/intel_dp.c    | 61 ++++++++++++++++++++++++++++++--------
>   drivers/gpu/drm/i915/intel_drv.h   |  2 ++
>   drivers/gpu/drm/i915/intel_panel.c | 27 +++++++++++++++++
>   3 files changed, 77 insertions(+), 13 deletions(-)
>