Commit c90b1551 authored by Ville Syrjälä's avatar Ville Syrjälä Committed by Jani Nikula
Browse files

drm/i915: Pick the backlight controller based on VBT on ICP+ 

Use the second backlight controller on ICP+ if the VBT asks
us to do so.

On pre-MTP we also check the chicken bit to make sure the
pins have been correctly muxed by the firmware.

Cc: stable@vger.kernel.org
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/8016


Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230207064337.18697-4-ville.syrjala@linux.intel.com


Reviewed-by: default avatarJani Nikula <jani.nikula@intel.com>
(cherry picked from commit b3377154)
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
parent 14e591a1

drivers/gpu/drm/i915/display/intel_backlight.c

+31 −3
Original line number Diff line number Diff line
@@ -1431,6 +1431,30 @@ bxt_setup_backlight(struct intel_connector *connector, enum pipe unused) 
	return 0;

}



static int cnp_num_backlight_controllers(struct drm_i915_private *i915)

{

	if (INTEL_PCH_TYPE(i915) >= PCH_DG1)

		return 1;



	if (INTEL_PCH_TYPE(i915) >= PCH_ICP)

		return 2;



	return 1;

}



static bool cnp_backlight_controller_is_valid(struct drm_i915_private *i915, int controller)

{

	if (controller < 0 || controller >= cnp_num_backlight_controllers(i915))

		return false;



	if (controller == 1 &&

	    INTEL_PCH_TYPE(i915) >= PCH_ICP &&

	    INTEL_PCH_TYPE(i915) < PCH_MTP)

		return intel_de_read(i915, SOUTH_CHICKEN1) & ICP_SECOND_PPS_IO_SELECT;



	return true;

}



static int

cnp_setup_backlight(struct intel_connector *connector, enum pipe unused)

{
@@ -1440,10 +1464,14 @@ cnp_setup_backlight(struct intel_connector *connector, enum pipe unused) 


	/*

	 * CNP has the BXT implementation of backlight, but with only one

	 * controller. TODO: ICP has multiple controllers but we only use

	 * controller 0 for now.

	 * controller. ICP+ can have two controllers, depending on pin muxing.

	 */

	panel->backlight.controller = connector->panel.vbt.backlight.controller;

	if (!cnp_backlight_controller_is_valid(i915, panel->backlight.controller)) {

		drm_dbg_kms(&i915->drm, "Invalid backlight controller %d, assuming 0\n",

			    panel->backlight.controller);

		panel->backlight.controller = 0;

	}



	pwm_ctl = intel_de_read(i915,

				BXT_BLC_PWM_CTL(panel->backlight.controller));