From patchwork Sat Oct 1 19:08:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marijn Suijten X-Patchwork-Id: 12996671 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 B856AC433F5 for ; Sat, 1 Oct 2022 19:08:55 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id C1A6C10E4F2; Sat, 1 Oct 2022 19:08:38 +0000 (UTC) Received: from relay01.th.seeweb.it (relay01.th.seeweb.it [5.144.164.162]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8B50110E4D0 for ; Sat, 1 Oct 2022 19:08:29 +0000 (UTC) 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-r1.th.seeweb.it (Postfix) with ESMTPSA id 6F37420377; Sat, 1 Oct 2022 21:08:27 +0200 (CEST) From: Marijn Suijten To: phone-devel@vger.kernel.org, Rob Clark , Dmitry Baryshkov , Vinod Koul Subject: [PATCH 4/5] drm/msm/dpu1: Account for DSC's bits_per_pixel having 4 fractional bits Date: Sat, 1 Oct 2022 21:08:06 +0200 Message-Id: <20221001190807.358691-5-marijn.suijten@somainline.org> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221001190807.358691-1-marijn.suijten@somainline.org> References: <20221001190807.358691-1-marijn.suijten@somainline.org> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: freedreno@lists.freedesktop.org, Douglas Anderson , Thomas Zimmermann , Jami Kettunen , Vladimir Lypak , linux-arm-msm@vger.kernel.org, Konrad Dybcio , Abhinav Kumar , dri-devel@lists.freedesktop.org, Javier Martinez Canillas , David Airlie , Martin Botka , ~postmarketos/upstreaming@lists.sr.ht, AngeloGioacchino Del Regno , Alex Deucher , Marijn Suijten , Sean Paul , linux-kernel@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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: Dmitry Baryshkov Reviewed-by: Abhinav Kumar --- 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 f2ddcfb6f7ee..3662df698dae 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c @@ -42,7 +42,7 @@ 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); @@ -56,14 +56,7 @@ 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);