From: Suraj Kandpal Date: Thu, 6 Feb 2025 06:32:50 +0000 (+0530) Subject: drm/i915/backlight: Modify function to get VESA brightness in Nits X-Git-Tag: v6.15-rc1~120^2~16^2~117 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3f8a009a794eac8f5b7fac0242d321cc4581303d;p=thirdparty%2Fkernel%2Flinux.git drm/i915/backlight: Modify function to get VESA brightness in Nits Modify vesa_get_brightness function to take into account luminance_control_support and based on that read the appropriate register and return the value. --v2 -Changes since we now use luminance instead of nits Signed-off-by: Suraj Kandpal Tested-by: Ben Kao Reviewed-by: Arun R Murthy Link: https://patchwork.freedesktop.org/patch/msgid/20250206063253.2827017-6-suraj.kandpal@intel.com --- 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 2599aa39b21df..ca5fc40fa13af 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c @@ -451,6 +451,26 @@ intel_dp_aux_hdr_setup_backlight(struct intel_connector *connector, enum pipe pi /* VESA backlight callbacks */ static u32 intel_dp_aux_vesa_get_backlight(struct intel_connector *connector, enum pipe unused) { + struct intel_dp *intel_dp = enc_to_intel_dp(connector->encoder); + struct intel_panel *panel = &connector->panel; + u8 buf[3]; + u32 val = 0; + int ret; + + if (panel->backlight.edp.vesa.luminance_control_support) { + ret = drm_dp_dpcd_read(&intel_dp->aux, DP_EDP_PANEL_TARGET_LUMINANCE_VALUE, buf, + sizeof(buf)); + if (ret < 0) { + drm_err(intel_dp->aux.drm_dev, + "[CONNECTOR:%d:%s] Failed to read Luminance from DPCD\n", + connector->base.base.id, connector->base.name); + return 0; + } + + val |= buf[0] | buf[1] << 8 | buf[2] << 16; + return val / 1000; + } + return connector->panel.backlight.level; }