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 B3690C433F5 for ; Wed, 23 Mar 2022 14:26:52 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C5D9110E75E; Wed, 23 Mar 2022 14:26:51 +0000 (UTC) Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by gabe.freedesktop.org (Postfix) with ESMTPS id BE4CF10E75E; Wed, 23 Mar 2022 14:26:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1648045610; x=1679581610; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=k/ljExPLhr/iCvWHx4Y7ER0bjNCsw3LGgldpOUp4+P0=; b=bD9hksCIStab16KFlKZnJvFrwklnKucofdenc/UnRdKsNMVOyPidrA6o paVWXYylKdrQCx+bjdiYCT2598K+g/CEpW0UOcyn0ZQSAmzi3nQCASIvP dBRi0Fh1L7fV36DM/6SRXrA8/u3MoMRXOOnaZAKaVxr0HHcl9AdOakjV4 l0FuGaxNsD4LBiUysrDD1ydNIk/8i6OFqZtvz76ZIXwfqhift6lbYpa5o gPYbjxqS5PBWjA+WCvrtban748hzaRoAn+ZJLklRuoj9FKOZ3P7eZX7HL Kh8ep//8eU4t6lQmTJaRb1TigQ8zqc5O44167E7N7h77u9KKxk8qjjKQx Q==; X-IronPort-AV: E=McAfee;i="6200,9189,10294"; a="240284139" X-IronPort-AV: E=Sophos;i="5.90,204,1643702400"; d="scan'208";a="240284139" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Mar 2022 07:26:50 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.90,204,1643702400"; d="scan'208";a="515794054" Received: from stinkpipe.fi.intel.com (HELO stinkbox) ([10.237.72.61]) by orsmga002.jf.intel.com with SMTP; 23 Mar 2022 07:26:46 -0700 Received: by stinkbox (sSMTP sendmail emulation); Wed, 23 Mar 2022 16:26:45 +0200 Date: Wed, 23 Mar 2022 16:26:45 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Jani Nikula Message-ID: References: <20220317124202.14189-1-shawn.c.lee@intel.com> <20220317124202.14189-4-shawn.c.lee@intel.com> <8735j9j7vd.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <8735j9j7vd.fsf@intel.com> X-Patchwork-Hint: comment Subject: Re: [Intel-gfx] [v8 3/5] drm/edid: read HF-EEODB ext block X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: cooper.chiou@intel.com, william.tseng@intel.com, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Wed, Mar 23, 2022 at 12:11:50PM +0200, Jani Nikula wrote: > On Thu, 17 Mar 2022, Lee Shawn C wrote: > > According to HDMI 2.1 spec. > > > > "The HDMI Forum EDID Extension Override Data Block (HF-EEODB) > > is utilized by Sink Devices to provide an alternate method to > > indicate an EDID Extension Block count larger than 1, while > > avoiding the need to present a VESA Block Map in the first > > E-EDID Extension Block." > > > > It is a mandatory for HDMI 2.1 protocol compliance as well. > > This patch help to know how many HF_EEODB blocks report by sink > > and read allo HF_EEODB blocks back. > > It still just boggles my mind that they've implemented something like > this. They cite avoiding the EDID Block Map as the rationale... but it's > been optional since E-EDID structure v1.4, published in 2006. 15+ years > ago. > > Can anyone tell me a sane reason for this? What does it provide that > E-EDID 1.4 does not? Do they want to use E-EDID v1.3 with this? Why? Looks to be pretty much the same approach as the DPCD extended receiver cap mess we already have to deal with. So I presume this is a hack to avoid breaking some garbage source devices that explode when they see too many extension blocks, or something along those lines. -- Ville Syrjälä Intel