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 X-Spam-Level: X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C3AAC432BE for ; Thu, 26 Aug 2021 11:11:32 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id E5A10610A1 for ; Thu, 26 Aug 2021 11:11:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E5A10610A1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 633B86E7D7; Thu, 26 Aug 2021 11:11:31 +0000 (UTC) Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3F8676E7D7; Thu, 26 Aug 2021 11:11:30 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10087"; a="217754688" X-IronPort-AV: E=Sophos;i="5.84,353,1620716400"; d="scan'208";a="217754688" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2021 04:11:29 -0700 X-IronPort-AV: E=Sophos;i="5.84,353,1620716400"; d="scan'208";a="527836656" Received: from jwhogabo-mobl2.amr.corp.intel.com (HELO localhost) ([10.249.45.163]) by fmsmga003-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Aug 2021 04:11:27 -0700 From: Jani Nikula To: Ville =?utf-8?B?U3lyasOkbMOk?= Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Manasi Navare , Lyude Paul In-Reply-To: <87eeahegw0.fsf@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <87eeahegw0.fsf@intel.com> Date: Thu, 26 Aug 2021 14:11:24 +0300 Message-ID: <87lf4ocvfn.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Intel-gfx] [PATCH 2/4] drm/dp: use more of the extended receiver cap 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: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Wed, 25 Aug 2021, Jani Nikula wrote: > On Thu, 19 Aug 2021, Ville Syrj=C3=A4l=C3=A4 wrote: >> On Fri, Aug 13, 2021 at 01:43:20PM +0300, Jani Nikula wrote: >>> Extend the use of extended receiver cap at 0x2200 to cover >>> MAIN_LINK_CHANNEL_CODING_CAP in 0x2206, in case an implementation hides >>> the DP 2.0 128b/132b channel encoding cap. >>>=20 >>> Cc: Manasi Navare >>> Signed-off-by: Jani Nikula >>> --- >>> drivers/gpu/drm/drm_dp_helper.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>=20 >>> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_h= elper.c >>> index 9b2a2961fca8..9389f92cb944 100644 >>> --- a/drivers/gpu/drm/drm_dp_helper.c >>> +++ b/drivers/gpu/drm/drm_dp_helper.c >>> @@ -608,7 +608,7 @@ static u8 drm_dp_downstream_port_count(const u8 dpc= d[DP_RECEIVER_CAP_SIZE]) >>> static int drm_dp_read_extended_dpcd_caps(struct drm_dp_aux *aux, >>> u8 dpcd[DP_RECEIVER_CAP_SIZE]) >>> { >>> - u8 dpcd_ext[6]; >>> + u8 dpcd_ext[DP_MAIN_LINK_CHANNEL_CODING + 1]; >> >> Why are we even reading less of this than the normal receiver caps? > > Good question. I forget my reasoning to only extend to what might affect > this use case. Should we extend to the size of the usual receiver caps? Ah, there was a previous discussion [1] with Lyude (Cc'd). BR, Jani. [1] https://patchwork.freedesktop.org/patch/msgid/20200901123226.4177-1-jan= i.nikula@intel.com > > BR, > Jani. > > >> >>> int ret; >>>=20=20 >>> /* >>> --=20 >>> 2.20.1 --=20 Jani Nikula, Intel Open Source Graphics Center