linux-kernel - [PATCH 1/2] drm/i915/dpcd_bl: uncheck PWM_PIN_CAP when detect eDP backlight capabilities

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Message-Id: <20201009085750.88490-1-aaron.ma@canonical.com>
Date:   Fri,  9 Oct 2020 16:57:49 +0800
From:   Aaron Ma <aaron.ma@...onical.com>
To:     linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        intel-gfx@...ts.freedesktop.org, aaron.ma@...onical.com,
        mapengyu@...il.com, daniel@...ll.ch, airlied@...ux.ie,
        tzimmermann@...e.de, mripard@...nel.org,
        maarten.lankhorst@...ux.intel.com, rodrigo.vivi@...el.com,
        joonas.lahtinen@...ux.intel.com, jani.nikula@...ux.intel.com,
        lyude@...hat.com, ville.syrjala@...ux.intel.com
Subject: [PATCH 1/2] drm/i915/dpcd_bl: uncheck PWM_PIN_CAP when detect eDP backlight capabilities

BOE panel with ID 2270 claims both PWM_PIN_CAP and AUX_SET_CAP backlight
control bits, but default chip backlight failed to control brightness.

Check AUX_SET_CAP and proceed to check quirks or VBT backlight type.
DPCD can control the brightness of this pannel.

Signed-off-by: Aaron Ma <aaron.ma@...onical.com>
---
 drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
index acbd7eb66cbe..308b14159b7c 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -334,8 +334,7 @@ intel_dp_aux_display_control_capable(struct intel_connector *connector)
 	 * the panel can support backlight control over the aux channel
 	 */
 	if (intel_dp->edp_dpcd[1] & DP_EDP_TCON_BACKLIGHT_ADJUSTMENT_CAP &&
-	    (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP) &&
-	    !(intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_PWM_PIN_CAP)) {
+	    (intel_dp->edp_dpcd[2] & DP_EDP_BACKLIGHT_BRIGHTNESS_AUX_SET_CAP)) {
 		drm_dbg_kms(&i915->drm, "AUX Backlight Control Supported!\n");
 		return true;
 	}
-- 
2.25.1