From patchwork Mon Mar 1 16:10:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 389899 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3096BC433E6 for ; Mon, 1 Mar 2021 17:42:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EDFB66532D for ; Mon, 1 Mar 2021 17:42:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238379AbhCARmV (ORCPT ); Mon, 1 Mar 2021 12:42:21 -0500 Received: from mail.kernel.org ([198.145.29.99]:54062 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238589AbhCARd5 (ORCPT ); Mon, 1 Mar 2021 12:33:57 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id C4355650A9; Mon, 1 Mar 2021 16:53:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614617614; bh=NzDcQ8lTX9om9ZZH8fgDUHt2fkdvcrw0G/E9TltytjA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZOzcRMJFqqZQmP5FTx/rsWIjdYN2gOVguG/JVt3fOpsZ0nc5EuTiEfVmYxRwtkMHp m9mmEEgjh8Q3193TkhvQn2R/i6I6onZcYK+Mf09l+8haNawByQr1FOqnkdNLHh5NgT iNDVaBx9ls8uuaeY2bh5qpkrUA5t/RuVWhq1NDZk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mario Kleiner , Harry Wentland , Alex Deucher , Sasha Levin Subject: [PATCH 5.4 095/340] drm/amd/display: Fix 10/12 bpc setup in DCE output bit depth reduction. Date: Mon, 1 Mar 2021 17:10:39 +0100 Message-Id: <20210301161053.003797717@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210301161048.294656001@linuxfoundation.org> References: <20210301161048.294656001@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Mario Kleiner [ Upstream commit 1916866dfa4aaceba1a70db83fde569387649d93 ] In set_clamp(), the comments and definitions for the COLOR_DEPTH_101010 and COLOR_DEPTH_121212 cases directly contradict the code comment which explains how this should work, whereas the COLOR_DEPTH_888 case is consistent with the code comments. Comment says the bitmask should be chosen to align to the top-most 10 or 12 MSB's on a 14 bit bus, but the implementation contradicts that: 10 bit case sets a mask for 12 bpc clamping, whereas 12 bit case sets a mask for 14 bpc clamping. Note that during my limited testing on DCE-8.3 (HDMI deep color) and DCE-11.2 (DP deep color), this didn't have any obvious ill effects, neither did fixing it change anything obvious for the better, so this fix may be inconsequential on DCE, and just reduce the confusion of innocent bystanders when reading the code and trying to investigate problems with 10 bpc+ output. Fixes: 4562236b3bc0 ("drm/amd/dc: Add dc display driver (v2)") Signed-off-by: Mario Kleiner Cc: Harry Wentland Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/display/dc/dce/dce_transform.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/dce/dce_transform.c b/drivers/gpu/drm/amd/display/dc/dce/dce_transform.c index ab63d0d0304cb..6fd57cfb112f5 100644 --- a/drivers/gpu/drm/amd/display/dc/dce/dce_transform.c +++ b/drivers/gpu/drm/amd/display/dc/dce/dce_transform.c @@ -429,12 +429,12 @@ static void set_clamp( clamp_max = 0x3FC0; break; case COLOR_DEPTH_101010: - /* 10bit MSB aligned on 14 bit bus '11 1111 1111 1100' */ - clamp_max = 0x3FFC; + /* 10bit MSB aligned on 14 bit bus '11 1111 1111 0000' */ + clamp_max = 0x3FF0; break; case COLOR_DEPTH_121212: - /* 12bit MSB aligned on 14 bit bus '11 1111 1111 1111' */ - clamp_max = 0x3FFF; + /* 12bit MSB aligned on 14 bit bus '11 1111 1111 1100' */ + clamp_max = 0x3FFC; break; default: clamp_max = 0x3FC0;