From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EEAE7E9B25E for ; Tue, 24 Feb 2026 12:31:28 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A8F5F10E568; Tue, 24 Feb 2026 12:31:28 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="VZ2W/E1I"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.10]) by gabe.freedesktop.org (Postfix) with ESMTPS id AA58010E568; Tue, 24 Feb 2026 12:31:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1771936288; x=1803472288; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=jNIE+vvrVQGGTBqFyIKa7vVsOCxiBa5OtyW+oajtXOI=; b=VZ2W/E1IIeV/8Iak+/W8w8RikN8oN4+HI0FiyPVH9cweg586FvVXeBdD 0cALFjyhf3iRJkmv78wSiklwpu0EPHA+w6mG+OhybkF7rGVC5Rf3NQFox mlOrBd52bIGjwTRlG1o5NXmzEE16/dJmE/dfCaTEnQxcI6UYfhXnpXMXy S7sj2L0rsmzKq3NvlS35SlpkZ21Fza+pGiKMYL2VV443YbqnMxtpRWOqs xXOBBAxb4h0aGAWpDSHXz84ogbNZmvzhIyc/bL/wQR7CT/5MDubwxAKA6 Jxg2YU3nhH+MWkd1rB78ZMO2BEz8Ok+4Nn40yIJ+vm4wuGTf1JYIgOgSl g==; X-CSE-ConnectionGUID: sKqXZx3VSIyXRgOI2I20wA== X-CSE-MsgGUID: busD8xsATcCTWtKgvMp3+w== X-IronPort-AV: E=McAfee;i="6800,10657,11710"; a="90360269" X-IronPort-AV: E=Sophos;i="6.21,308,1763452800"; d="scan'208";a="90360269" Received: from orviesa007.jf.intel.com ([10.64.159.147]) by orvoesa102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Feb 2026 04:31:28 -0800 X-CSE-ConnectionGUID: jwzPOXGaR3iRVTiOBodkGw== X-CSE-MsgGUID: dSPoh31DSi67+bqRXq0Syg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.21,308,1763452800"; d="scan'208";a="216054520" Received: from ettammin-mobl2.ger.corp.intel.com (HELO localhost) ([10.245.246.20]) by orviesa007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Feb 2026 04:31:26 -0800 From: Jani Nikula To: Suraj Kandpal , intel-xe@lists.freedesktop.org, intel-gfx@lists.freedesktop.org Cc: arun.r.murthy@intel.com, Suraj Kandpal Subject: Re: [PATCH v3 1/8] drm/i915/backlight: Use default/max brightness for VESA AUX backlight init In-Reply-To: <20260224034526.2730130-2-suraj.kandpal@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs Bertel Jungin Aukio 5, 02600 Espoo, Finland References: <20260224034526.2730130-1-suraj.kandpal@intel.com> <20260224034526.2730130-2-suraj.kandpal@intel.com> Date: Tue, 24 Feb 2026 14:31:22 +0200 Message-ID: <1a76dfe14cbc90b4aaec6f0e54b4e8df9f480efa@intel.com> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Tue, 24 Feb 2026, Suraj Kandpal wrote: > If the brightness fetched from VBT/previous state is 0 on backlight > initialization, then set the brightness to a default/max value. > Whenever the minimum brightness is reported as 0 there are chances > we end up with blank screen. This confuses the user into thinking > the display is acting weird. This occurs in eDP 1.5 when > we are using PANEL_LUMINANCE_OVERRIDE mode to mainpulate brightness > via luminance values. > > Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/15671 > Signed-off-by: Suraj Kandpal > Reviewed-by: Arun R Murthy > --- > v1 -> v2: > - Let users set brightness to 0, make it so that it's just not > done by default (Arun) > > v2 -> v3: > -Update commit header and message (Arun) > > drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 4 ++++ > 1 file changed, 4 insertions(+) > > 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 eb05ef4bd9f6..c40ce310ad97 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c > @@ -564,6 +564,8 @@ static int intel_dp_aux_vesa_setup_backlight(struct intel_connector *connector, > } > panel->backlight.level = intel_dp_aux_vesa_get_backlight(connector, 0); > panel->backlight.enabled = panel->backlight.level != 0; > + if (!panel->backlight.level) > + panel->backlight.level = panel->backlight.max; How does this help when .enabled is still based on level != 0 above? > drm_dbg_kms(display->drm, > "[CONNECTOR:%d:%s] AUX VESA Nits backlight level is controlled through DPCD\n", > connector->base.base.id, connector->base.name); > @@ -573,6 +575,8 @@ static int intel_dp_aux_vesa_setup_backlight(struct intel_connector *connector, > if (current_mode == DP_EDP_BACKLIGHT_CONTROL_MODE_DPCD) { > panel->backlight.level = current_level; > panel->backlight.enabled = panel->backlight.level != 0; > + if (!panel->backlight.level) > + panel->backlight.level = panel->backlight.max; Ditto. > } else { > panel->backlight.level = panel->backlight.max; > panel->backlight.enabled = false; -- Jani Nikula, Intel