From patchwork Wed Oct 26 18:28:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marijn Suijten X-Patchwork-Id: 618874 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 CA24AC433FE for ; Wed, 26 Oct 2022 18:28:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233960AbiJZS2s (ORCPT ); Wed, 26 Oct 2022 14:28:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234375AbiJZS2i (ORCPT ); Wed, 26 Oct 2022 14:28:38 -0400 Received: from m-r2.th.seeweb.it (m-r2.th.seeweb.it [5.144.164.171]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 476BEDFC2B; Wed, 26 Oct 2022 11:28:37 -0700 (PDT) Received: from localhost.localdomain (94-209-172-39.cable.dynamic.v4.ziggo.nl [94.209.172.39]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by m-r2.th.seeweb.it (Postfix) with ESMTPSA id 3A52E3F412; Wed, 26 Oct 2022 20:28:35 +0200 (CEST) From: Marijn Suijten To: phone-devel@vger.kernel.org, Rob Clark , Abhinav Kumar , Dmitry Baryshkov , Vinod Koul Cc: ~postmarketos/upstreaming@lists.sr.ht, AngeloGioacchino Del Regno , Konrad Dybcio , Martin Botka , Jami Kettunen , Marijn Suijten , Sean Paul , David Airlie , Daniel Vetter , Douglas Anderson , Vladimir Lypak , linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 01/10] drm/msm/dsi: Remove useless math in DSC calculations Date: Wed, 26 Oct 2022 20:28:15 +0200 Message-Id: <20221026182824.876933-2-marijn.suijten@somainline.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221026182824.876933-1-marijn.suijten@somainline.org> References: <20221026182824.876933-1-marijn.suijten@somainline.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org Multiplying a value by 2 and adding 1 to it always results in a value that is uneven, and that 1 gets truncated immediately when performing integer division by 2 again. There is no "rounding" possible here. After that target_bpp_x16 is used to store a multiplication of bits_per_pixel by 16 which is only ever read to immediately be divided by 16 again, and is elided in much the same way. Fixes: b9080324d6ca ("drm/msm/dsi: add support for dsc data") Reviewed-by: Abhinav Kumar Reviewed-by: Dmitry Baryshkov Signed-off-by: Marijn Suijten --- drivers/gpu/drm/msm/dsi/dsi_host.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c index e82eef031ed4..d645fcbb0683 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_host.c +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c @@ -1784,7 +1784,6 @@ static int dsi_populate_dsc_params(struct drm_dsc_config *dsc) int hrd_delay; int pre_num_extra_mux_bits, num_extra_mux_bits; int slice_bits; - int target_bpp_x16; int data; int final_value, final_scale; int i; @@ -1864,14 +1863,7 @@ static int dsi_populate_dsc_params(struct drm_dsc_config *dsc) data = 2048 * (dsc->rc_model_size - dsc->initial_offset + num_extra_mux_bits); dsc->slice_bpg_offset = DIV_ROUND_UP(data, groups_total); - /* bpp * 16 + 0.5 */ - data = dsc->bits_per_pixel * 16; - data *= 2; - data++; - data /= 2; - target_bpp_x16 = data; - - data = (dsc->initial_xmit_delay * target_bpp_x16) / 16; + data = dsc->initial_xmit_delay * dsc->bits_per_pixel; final_value = dsc->rc_model_size - data + num_extra_mux_bits; dsc->final_offset = final_value;