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 42C15C433FE for ; Mon, 13 Dec 2021 12:30:57 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3E76910E8DD; Mon, 13 Dec 2021 12:30:56 +0000 (UTC) Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6A22B10E8DD for ; Mon, 13 Dec 2021 12:30:55 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10196"; a="262846461" X-IronPort-AV: E=Sophos;i="5.88,202,1635231600"; d="scan'208";a="262846461" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Dec 2021 04:30:54 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.88,202,1635231600"; d="scan'208";a="544760066" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.171]) by orsmga001.jf.intel.com with SMTP; 13 Dec 2021 04:30:52 -0800 Received: by stinkbox (sSMTP sendmail emulation); Mon, 13 Dec 2021 14:30:51 +0200 Date: Mon, 13 Dec 2021 14:30:51 +0200 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Lee Shawn C Subject: Re: [PATCH] drm/edid: Refine HDMI VSDB detect Message-ID: References: <20211212153331.15457-1-shawn.c.lee@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20211212153331.15457-1-shawn.c.lee@intel.com> X-Patchwork-Hint: comment 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: , Cc: Dave Airlie , dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Sun, Dec 12, 2021 at 11:33:31PM +0800, Lee Shawn C wrote: > According to CEA-861-F chapter 7.5.4. It says "The VSDB shall contain the > 3 bytes of the IEEE OUI as well as any additional payload bytes needed." > Now DRM driver check HDMI OUI but VSDB payload size at least five bytes. > That may caused some HDMI monitors' audio feature can't be enabled. > Because of they only have three bytes payload (OUI only) in VSDB. HDMI 1.4a says "Sinks shall contain an HDMI VSDB minimally containing a 2-byte Source Physical Address field following the 24-bit identifier. ... The minimum value of N (length) is 5 and the maximum value of N is 31." Do you actually have an EDID that violates that? > > Cc: Ville Syrjälä > Cc: Adam Jackson > Cc: Dave Airlie > Signed-off-by: Lee Shawn C > --- > 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 12893e7be89b..5aa4a6bf4a13 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -4205,7 +4205,7 @@ static bool cea_db_is_hdmi_vsdb(const u8 *db) > if (cea_db_tag(db) != VENDOR_BLOCK) > return false; > > - if (cea_db_payload_len(db) < 5) > + if (cea_db_payload_len(db) < 3) > return false; > > return oui(db[3], db[2], db[1]) == HDMI_IEEE_OUI; > -- > 2.31.1 -- Ville Syrjälä Intel