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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD95BC433FE for ; Mon, 13 Dec 2021 09:38:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234372AbhLMJib (ORCPT ); Mon, 13 Dec 2021 04:38:31 -0500 Received: from mga05.intel.com ([192.55.52.43]:13602 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234830AbhLMJhE (ORCPT ); Mon, 13 Dec 2021 04:37:04 -0500 X-IronPort-AV: E=McAfee;i="6200,9189,10196"; a="324966583" X-IronPort-AV: E=Sophos;i="5.88,202,1635231600"; d="scan'208";a="324966583" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Dec 2021 01:34:15 -0800 X-IronPort-AV: E=Sophos;i="5.88,202,1635231600"; d="scan'208";a="464555913" Received: from ppolasze-mobl.ger.corp.intel.com (HELO localhost) ([10.252.20.7]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Dec 2021 01:34:12 -0800 From: Jani Nikula To: Kees Cook Cc: Harry Wentland , David Airlie , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-hardening@vger.kernel.org, Thomas Zimmermann , Thierry Reding Subject: Re: [PATCH] drm/dp: Actually read Adjust Request Post Cursor2 register In-Reply-To: <202112100853.FDB294B86@keescook> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20211203084354.3105253-1-keescook@chromium.org> <87o85r4a4f.fsf@intel.com> <202112082220.81ECDC63D@keescook> <2b7d760c-9ab8-b607-efc6-1ed276d67668@amd.com> <202112091539.6B349AC@keescook> <87a6h83hb7.fsf@intel.com> <202112100853.FDB294B86@keescook> Date: Mon, 13 Dec 2021 11:34:09 +0200 Message-ID: <87y24o7sry.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org On Fri, 10 Dec 2021, Kees Cook wrote: > On Fri, Dec 10, 2021 at 12:06:20PM +0200, Jani Nikula wrote: >> Post Cursor2 was completely optional for the transmitter even before it >> was deprecated. >> >> And now we'd be adding 5 bytes extra to all link status reads. To fix >> the only user of drm_dp_get_adjust_request_post_cursor() that apparently >> has never worked as intended. I'm just not convinced. >> >> I was trying to look through the implications of DP_LINK_STATUS_SIZE >> increase, and at least drm_dp_dpcd_read_phy_link_status() comes across >> as something probably needing attention. > > Okay, it sounds like you'd prefer the "make it tegra-specific" patch I > proposed. I will work that up as a proper patch and send it. Yes. Of course, I'd like to hear Thierry's view as well. BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center