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 D693DC433F5 for ; Wed, 23 Mar 2022 10:40:30 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 401FC10E676; Wed, 23 Mar 2022 10:40:30 +0000 (UTC) Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by gabe.freedesktop.org (Postfix) with ESMTPS id BEDA510E676 for ; Wed, 23 Mar 2022 10:40:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1648032028; x=1679568028; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=QKBsDAl7oTCzEC4w+3YYwec2NF40yUtoTtGwHajI2+s=; b=Bv9N6XilMY78Iqjidcvt42YG2HgpqmGm/qCmPSHJ7ZcBG/7mvJaR8vuN Qzrw30smy3HR1zt7tZ4ULPg4+Gljdxz6yT2pfoD35Sch+CQX95KJmOv97 APfTS3M5UCB1jl49KzuKK3iNfhr7inXCD1XmpYVtRoRS78vbsYgqXfBew 3VKyUSJ9hpPd+r+Pt5FnW8OBkN6HSuE7iu/MErR08UKGn2k846RfTwaGC LlvDZ4GLFxjJD6gE25W3tjeRFUZS9mDxub1o9xraUuP0zGumn1Ln5juLQ Oknvh5EPvutvLEQaaJy+Iw06ulh5isGn6+o62+cH5U3lJtxLqZ3vLme1/ w==; X-IronPort-AV: E=McAfee;i="6200,9189,10294"; a="245551503" X-IronPort-AV: E=Sophos;i="5.90,203,1643702400"; d="scan'208";a="245551503" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Mar 2022 03:40:28 -0700 X-IronPort-AV: E=Sophos;i="5.90,203,1643702400"; d="scan'208";a="544138683" Received: from caliyanx-mobl.gar.corp.intel.com (HELO localhost) ([10.252.57.47]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 Mar 2022 03:40:26 -0700 From: Jani Nikula To: "Lee, Shawn C" , "Chiou, Cooper" , "intel-gfx@lists.freedesktop.org" In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20220321044330.27723-1-cooper.chiou@intel.com> <875yo5j88o.fsf@intel.com> Date: Wed, 23 Mar 2022 12:40:23 +0200 Message-ID: <87wnglhrzc.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Intel-gfx] [PATCH] drm/edid: filter DisplayID v2.0 CTA block in audio detection 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: "Chiou, Cooper" Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Wed, 23 Mar 2022, "Lee, Shawn C" wrote: > On Wednesday, March 23, 2022 6:04 PM, Nikula, Jani wrote : >>On Mon, 21 Mar 2022, Cooper Chiou wrote: >>> In DisplayID v2.0 CTS data block 0x81 case, there is no any audio >>> information definition, but drm_detect_monitor_audio didn't filter it >>> so that it caused eDP dummy audio card be detected improperly. >>> >>> We observed this issue on some AUO/BOE eDP panel with DID v2.0 CTA >>> block, and fix issue by adding filter for edid_ext[0]=DATA_BLOCK_CTA >>> case. >> >>Out of curiosity, what does the CTA DisplayID Data Block have for Data Block revision? >> >>I haven't found any mention anywhere that it should have any correspondence to the CEA *extension* revision number, which is supposed to be 1..3, and really only 3 for about a decade now. >> >>Both the DisplayID v1.3 and v2.0 specs only mention revision 0. >> >>BR, >>Jani. >> > > We don't get many issues in EDID with DisplayID structure. In this case, the revision number is "0" as well. > As you mentioned, DisplayID v1.3 and v2.0 spec define the block revision value is always 0. Do you think it would cause any problem? A lot of places in the EDID parser expect CEA revision >= 3. This isn't true for DisplayID data blocks, so we end up skipping a bunch of stuff if there's no CEA extension and only a DisplayID block. I'm fixing this in my series. BR, Jani. > > Best regards, > Shawn > >>> >>> Cc: Jani Nikula >>> Cc: Shawn C Lee >>> >>> Signed-off-by: Cooper Chiou >>> --- >>> drivers/gpu/drm/drm_edid.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c >>> index f5f5de362ff2..6c9ae4b130bd 100644 >>> --- a/drivers/gpu/drm/drm_edid.c >>> +++ b/drivers/gpu/drm/drm_edid.c >>> @@ -4845,7 +4845,7 @@ bool drm_detect_monitor_audio(struct edid *edid) >>> int start_offset, end_offset; >>> >>> edid_ext = drm_find_cea_extension(edid); >>> - if (!edid_ext) >>> + if (!edid_ext || (edid_ext[0] == DATA_BLOCK_CTA)) >>> goto end; >>> >>> has_audio = ((edid_ext[3] & EDID_BASIC_AUDIO) != 0); >> >>-- >>Jani Nikula, Intel Open Source Graphics Center >> -- Jani Nikula, Intel Open Source Graphics Center