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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 669B0C433EF for ; Tue, 26 Oct 2021 17:07:50 +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 1D99260E8F for ; Tue, 26 Oct 2021 17:07:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 1D99260E8F 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 9086789C9D; Tue, 26 Oct 2021 17:07:49 +0000 (UTC) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTPS id EE06789C9D for ; Tue, 26 Oct 2021 17:07:48 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10149"; a="230224687" X-IronPort-AV: E=Sophos;i="5.87,184,1631602800"; d="scan'208";a="230224687" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Oct 2021 09:05:19 -0700 X-IronPort-AV: E=Sophos;i="5.87,184,1631602800"; d="scan'208";a="497408850" Received: from flaboura-mobl.ger.corp.intel.com (HELO localhost) ([10.251.214.127]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Oct 2021 09:05:16 -0700 From: Jani Nikula To: Ville =?utf-8?B?U3lyasOkbMOk?= Cc: intel-gfx@lists.freedesktop.org, Manasi Navare In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20211026084208.2574-1-jani.nikula@intel.com> <20211026093407.11381-1-jani.nikula@intel.com> Date: Tue, 26 Oct 2021 19:05:13 +0300 Message-ID: <877ddzkc06.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Intel-gfx] [PATCH v2] drm/i915/dp: fix integer overflow in 128b/132b data rate calculation 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 Tue, 26 Oct 2021, Ville Syrj=C3=A4l=C3=A4 wrote: > On Tue, Oct 26, 2021 at 12:34:07PM +0300, Jani Nikula wrote: >> The intermediate value 1000000 * 10 * 9671 overflows 32 bits, so force >> promotion to a bigger type. >>=20 >> >From the logs: >>=20 >> [drm:intel_dp_compute_config [i915]] DP link rate required 3657063 avail= able -580783288 >>=20 >> v2: Use mul_u32_u32() (Ville) >>=20 >> Fixes: 48efd014f0ea ("drm/i915/dp: add max data rate calculation for UHB= R rates") >> Cc: Manasi Navare >> Cc: Ville Syrj=C3=A4l=C3=A4 >> Signed-off-by: Jani Nikula > > Reviewed-by: Ville Syrj=C3=A4l=C3=A4 Thanks, pushed. BR, Jani. > >> --- >> drivers/gpu/drm/i915/display/intel_dp.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >>=20 >> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i= 915/display/intel_dp.c >> index f5dc2126d140..537c689a1528 100644 >> --- a/drivers/gpu/drm/i915/display/intel_dp.c >> +++ b/drivers/gpu/drm/i915/display/intel_dp.c >> @@ -352,7 +352,7 @@ intel_dp_max_data_rate(int max_link_rate, int max_la= nes) >> */ >> int max_link_rate_kbps =3D max_link_rate * 10; >>=20=20 >> - max_link_rate_kbps =3D DIV_ROUND_CLOSEST_ULL(max_link_rate_kbps * 967= 1, 10000); >> + max_link_rate_kbps =3D DIV_ROUND_CLOSEST_ULL(mul_u32_u32(max_link_rat= e_kbps, 9671), 10000); >> max_link_rate =3D max_link_rate_kbps / 8; >> } >>=20=20 >> --=20 >> 2.30.2 --=20 Jani Nikula, Intel Open Source Graphics Center