From mboxrd@z Thu Jan 1 00:00:00 1970 From: Clint Taylor Subject: Re: [PATCH 3/4] drm/i915/dp: make backlight bl_power control power sequencer backlight Date: Mon, 18 Aug 2014 10:44:16 -0700 Message-ID: <53F23B70.4080008@intel.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mga03.intel.com (mga03.intel.com [143.182.124.21]) by gabe.freedesktop.org (Postfix) with ESMTP id 3CA5F8908E for ; Mon, 18 Aug 2014 10:45:27 -0700 (PDT) In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Jani Nikula , intel-gfx@lists.freedesktop.org Cc: rodrigo.vivi@intel.com, kevin.strasser@intel.com, jesse.barnes@intel.com List-Id: intel-gfx@lists.freedesktop.org On 08/12/2014 07:11 AM, Jani Nikula wrote: > This lets the userspace switch off the backlight using the backlight > class sysfs bl_power file. The switch is done using the power sequencer; > the backlight PWM, and everything else, remains enabled. The display > backlight won't draw power, but for maximum power savings the encoder > needs to be switched off. > > Signed-off-by: Jani Nikula > --- > drivers/gpu/drm/i915/intel_dp.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c > index d8baf60ff3fd..f6e3e9a906b0 100644 > --- a/drivers/gpu/drm/i915/intel_dp.c > +++ b/drivers/gpu/drm/i915/intel_dp.c > @@ -1453,6 +1453,27 @@ void intel_edp_backlight_off(struct intel_dp *intel_dp) > intel_panel_disable_backlight(intel_dp->attached_connector); > } > > +/* > + * Hook for controlling the panel power control backlight through the bl_power > + * sysfs attribute. Take care to handle multiple calls. > + */ > +static void intel_edp_backlight_power(struct intel_connector *connector, > + bool enable) > +{ > + struct intel_dp *intel_dp = intel_attached_dp(&connector->base); > + bool is_enabled = ironlake_get_pp_control(intel_dp) & EDP_BLC_ENABLE; > + > + if (is_enabled == enable) > + return; > + > + DRM_DEBUG_KMS("\n"); > + > + if (enable) > + _intel_edp_backlight_on(intel_dp); > + else > + _intel_edp_backlight_off(intel_dp); Is there a good reason why we leave the PWM enabled? There is a small power requirement to leave the PWM enabled. > +} > + > static void ironlake_edp_pll_on(struct intel_dp *intel_dp) > { > struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp); > @@ -4579,6 +4600,7 @@ static bool intel_edp_init_connector(struct intel_dp *intel_dp, > } > > intel_panel_init(&intel_connector->panel, fixed_mode, downclock_mode); > + intel_connector->panel.backlight_power = intel_edp_backlight_power; > intel_panel_setup_backlight(connector); > > return true; >