From patchwork Wed Oct 26 18:28:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marijn Suijten X-Patchwork-Id: 619644 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 11A9DC38A2D for ; Wed, 26 Oct 2022 18:29:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234463AbiJZS3L (ORCPT ); Wed, 26 Oct 2022 14:29:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234393AbiJZS2y (ORCPT ); Wed, 26 Oct 2022 14:28:54 -0400 Received: from relay08.th.seeweb.it (relay08.th.seeweb.it [5.144.164.169]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A09A0E0715 for ; Wed, 26 Oct 2022 11:28:52 -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 868443F412; Wed, 26 Oct 2022 20:28:50 +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 09/10] drm/msm/dpu1: Account for DSC's bits_per_pixel having 4 fractional bits Date: Wed, 26 Oct 2022 20:28:23 +0200 Message-Id: <20221026182824.876933-10-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 According to the comment this DPU register contains the bits per pixel as a 6.4 fractional value, conveniently matching the contents of bits_per_pixel in struct drm_dsc_config which also uses 4 fractional bits. However, the downstream source this implementation was copy-pasted from has its bpp field stored _without_ fractional part. This makes the entire convoluted math obsolete as it is impossible to pull those 4 fractional bits out of thin air, by somehow trying to reuse the lowest 2 bits of a non-fractional bpp (lsb = bpp % 4??). The rest of the code merely attempts to keep the integer part a multiple of 4, which is rendered useless thanks to data |= dsc->bits_per_pixel << 12; already filling up those bits anyway (but not on downstream). Fixes: c110cfd1753e ("drm/msm/disp/dpu1: Add support for DSC") Signed-off-by: Marijn Suijten Reviewed-by: Abhinav Kumar Reviewed-by: Dmitry Baryshkov Reviewed-by: Vinod Koul --- drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c index d3aa062d5ed9..34244bed4a62 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c @@ -45,7 +45,7 @@ static void dpu_hw_dsc_config(struct dpu_hw_dsc *hw_dsc, u32 initial_lines) { struct dpu_hw_blk_reg_map *c = &hw_dsc->hw; - u32 data, lsb, bpp; + u32 data; u32 slice_last_group_size; u32 det_thresh_flatness; bool is_cmd_mode = !(mode & DSC_MODE_VIDEO); @@ -59,14 +59,7 @@ static void dpu_hw_dsc_config(struct dpu_hw_dsc *hw_dsc, data = (initial_lines << 20); data |= ((slice_last_group_size - 1) << 18); /* bpp is 6.4 format, 4 LSBs bits are for fractional part */ - data |= dsc->bits_per_pixel << 12; - lsb = dsc->bits_per_pixel % 4; - bpp = dsc->bits_per_pixel / 4; - bpp *= 4; - bpp <<= 4; - bpp |= lsb; - - data |= bpp << 8; + data |= (dsc->bits_per_pixel << 8); data |= (dsc->block_pred_enable << 7); data |= (dsc->line_buf_depth << 3); data |= (dsc->simple_422 << 2);