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 94E02C71153 for ; Mon, 4 Sep 2023 02:53:23 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7CF4D10E282; Mon, 4 Sep 2023 02:53:18 +0000 (UTC) Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.65]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0F8EC10E281; Mon, 4 Sep 2023 02:53:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1693795996; x=1725331996; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=PdSreeHi69xtNSRx7r99DqJLAzGyuw0+MVwLHFkzqMU=; b=Z6V6YNZi3ZinCX1yi3cHOKwEjgMwyLd/E0xhY5V+RDVTe29aXgXLK53b uFK2Wii7yQbrD0xKDmO6S37nmn43bosHSprebXSRqmnMic2P/il8QzgWo nhpcbyb8HcIuFEA81zFaLy0Q1i7dLME8YIuTBPE+wF3zWO44+hDPwQS4I kjO79cQ12YaukBMuGNMa5Hwk2mk9s+qNzelKOyyITiHWgtUwlHs2a8rVS i7uaTNZEyufuyHvY/y0rsiF5jFzVhgzUbvfA2UnsT1zzSIHfcfNhI7dr6 xki0HVXZHBYKfeHUgzj2HbhXZjbdJRW8YoOYjG/QlcbhXEZR0d79UO7ir A==; X-IronPort-AV: E=McAfee;i="6600,9927,10822"; a="380297323" X-IronPort-AV: E=Sophos;i="6.02,225,1688454000"; d="scan'208";a="380297323" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Sep 2023 19:53:15 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10822"; a="883879938" X-IronPort-AV: E=Sophos;i="6.02,225,1688454000"; d="scan'208";a="883879938" Received: from stinkpipe.fi.intel.com (HELO stinkbox) ([10.237.72.153]) by fmsmga001.fm.intel.com with SMTP; 03 Sep 2023 19:53:08 -0700 Received: by stinkbox (sSMTP sendmail emulation); Mon, 04 Sep 2023 05:53:11 +0300 Date: Mon, 4 Sep 2023 05:53:11 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Imre Deak Message-ID: References: <20230824080517.693621-1-imre.deak@intel.com> <20230824080517.693621-10-imre.deak@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230824080517.693621-10-imre.deak@intel.com> X-Patchwork-Hint: comment Subject: Re: [Intel-gfx] [PATCH v2 09/22] drm/dp_mst: Fix fractional bpp scaling in drm_dp_calc_pbn_mode() 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: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Thu, Aug 24, 2023 at 11:05:04AM +0300, Imre Deak wrote: > For fractional bpp values passed to the function in a .4 fixed point > format, the fractional part is currently ignored due to scaling bpp too > early. Fix this by scaling the overhead factor instead and to avoid an > overflow multiplying bpp with the overhead factor instead of the clock > rate. > > While at it simplify the formula, and pass the expected fixed point bpp > values in the kunit tests. > > Cc: Lyude Paul > Cc: dri-devel@lists.freedesktop.org > Signed-off-by: Imre Deak > --- > drivers/gpu/drm/display/drm_dp_mst_topology.c | 7 ++----- > drivers/gpu/drm/tests/drm_dp_mst_helper_test.c | 8 ++++---- > 2 files changed, 6 insertions(+), 9 deletions(-) > > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c > index ed96cfcfa3040..bd0f35a0ea5fb 100644 > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c > @@ -4712,12 +4712,9 @@ int drm_dp_calc_pbn_mode(int clock, int bpp, bool dsc) > * factor in the numerator rather than the denominator to avoid > * integer overflow > */ > + u32 bpp_m = (dsc ? 64 / 16 : 64) * 1006 * bpp; > > - if (dsc) > - return DIV_ROUND_UP_ULL(mul_u32_u32(clock * (bpp / 16), 64 * 1006), > - 8 * 54 * 1000 * 1000); > - > - return DIV_ROUND_UP_ULL(mul_u32_u32(clock * bpp, 64 * 1006), > + return DIV_ROUND_UP_ULL(mul_u32_u32(clock, bpp_m), > 8 * 54 * 1000 * 1000); I thought I sorted out this mess already... https://patchwork.freedesktop.org/patch/535005/?series=117201&rev=3 Apparently I forgot to push that. > } > EXPORT_SYMBOL(drm_dp_calc_pbn_mode); > diff --git a/drivers/gpu/drm/tests/drm_dp_mst_helper_test.c b/drivers/gpu/drm/tests/drm_dp_mst_helper_test.c > index 545beea33e8c7..ea2182815ebe8 100644 > --- a/drivers/gpu/drm/tests/drm_dp_mst_helper_test.c > +++ b/drivers/gpu/drm/tests/drm_dp_mst_helper_test.c > @@ -40,15 +40,15 @@ static const struct drm_dp_mst_calc_pbn_mode_test drm_dp_mst_calc_pbn_mode_cases > }, > { > .clock = 332880, > - .bpp = 24, > + .bpp = 24 << 4, > .dsc = true, > - .expected = 50 > + .expected = 1191 > }, > { > .clock = 324540, > - .bpp = 24, > + .bpp = 24 << 4, > .dsc = true, > - .expected = 49 > + .expected = 1161 > }, > }; > > -- > 2.37.2 -- Ville Syrjälä Intel