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 857B8F428C8 for ; Wed, 15 Apr 2026 19:16:42 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 8136D10E73D; Wed, 15 Apr 2026 19:16:41 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="GFjTEZc7"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3EA1B10E74D; Wed, 15 Apr 2026 19:16:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1776280599; x=1807816599; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=u9Jk6XIJWWR1cJ56Q1L2GEys47wi/1PVK05xIE3RW7E=; b=GFjTEZc7ZCaeDI23BFBXa+L+OGvCteqTO6lYkWjX6DmDLBtuLVnfpeLo ZyXxXw9lO0avXUtGgSzt0CGL3I0EbZYPZ8O9m07Zt70KuczMgARUhptbC W+WOkh47SyE9k5UnjQyRB8+pB5CT+dDXKUN3rFkN0oqXUMNEvm3GRqcI8 FKVU+RrL8rX/qMQ3gzsKKPd1LzeQkuWcyOGKvZsSNbRsyF49A063r5yuk U1f78DJ4UOn1aFqVdYhZbyYIQGFhxeXjYwNjwHlwNkRhQP2F1otoZZVxh cGtCn2zlpEXSgAmM9BhEtyCvxloKVBvvAzmXJ9kZcL4exUlNuvea6cdIA w==; X-CSE-ConnectionGUID: PFK+mSwCRUCZkaIyz3J3Hw== X-CSE-MsgGUID: Xygyorb3SLaWIiFqMLW6IQ== X-IronPort-AV: E=McAfee;i="6800,10657,11760"; a="102735580" X-IronPort-AV: E=Sophos;i="6.23,179,1770624000"; d="scan'208";a="102735580" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Apr 2026 12:16:39 -0700 X-CSE-ConnectionGUID: XMFb1mE4T1+16wGKQTjYIg== X-CSE-MsgGUID: Zmenxb6jQPyuRTcRJoQQbw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,179,1770624000"; d="scan'208";a="230359127" Received: from abityuts-desk.ger.corp.intel.com (HELO localhost) ([10.245.244.108]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Apr 2026 12:16:37 -0700 Date: Wed, 15 Apr 2026 22:16:34 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Jake S Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH 2/2] drm/i915/display: allow eDP VRR when EDID has adaptive sync range Message-ID: References: <20260415130626.10523-1-j@metarealtyinc.ca> <20260415130626.10523-3-j@metarealtyinc.ca> <69dfe22f.050a0220.301b30.5755@mx.google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <69dfe22f.050a0220.301b30.5755@mx.google.com> X-Patchwork-Hint: comment Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs Bertel Jungin Aukio 5, 02600 Espoo, Finland X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, Apr 15, 2026 at 07:08:30PM +0000, Jake S wrote: > Hi Ville, > > > AFAICS the Windows driver does respect that VBT bit. So we should too. > > That's fair -- I don't have visibility into the Windows driver > internals so I can't say definitively whether it checks VBT or not. > > What I can confirm is the end-user result: on this Dell XPS 2026 > (Panther Lake), VRR 20-120Hz works on Windows but not on Linux with > the same firmware. The VBT does not contain a VRR flag for this panel > at all -- intel_vbt_decode shows no VRR-related fields in the child > device block. It's in the LFP power block (44). > > So either Windows has a fallback path when VBT doesn't declare VRR, > or Dell's Intel DCH driver ships with a driver-side override. My cursory glance didn't spot any registry key stuff in there either. That I think is the usual "screw proper design and just hack it" approach for the Windows driver. > Either > way, the panel clearly supports VRR (the EDID's DisplayID extension > explicitly declares Adaptive Sync 20-120Hz), and it works in practice > on this hardware. > > Framework laptop users have reported the same class of issue with > their BOE panels. > > If respecting VBT is important (and I understand the reasoning -- > OEM validation), would something like a quirk table or a module > parameter be an acceptable alternative? I'd rather have any path to > making this work than no path. One can always hack up the VBT and use the firmware loader to override it. -- Ville Syrjälä Intel