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 X-Spam-Level: X-Spam-Status: No, score=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 5EA38C433E2 for ; Tue, 1 Sep 2020 16:03:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 38865206A5 for ; Tue, 1 Sep 2020 16:03:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598976236; bh=hEcf91JbzgPXRuztevJtJxtp78NU32tVPVA7ZRUoHnU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=orq2tXLZ87aRKY9JOJem35EdLbcT8jYsd26Svyfei6EQkqlGDAfY7YQ6eO6mbO04g sjqr4RInlrs71iOwYj96vAS67RwKR7Lc2fzAkxtzSffURyYt0WyCvF7bS23x+vTz0Q l5mhsKqfYTQ9w25m09YtfRQSMu8DEn9lt2r0zdOc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729718AbgIAQDv (ORCPT ); Tue, 1 Sep 2020 12:03:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:55588 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731565AbgIAPmf (ORCPT ); Tue, 1 Sep 2020 11:42:35 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 055E92064B; Tue, 1 Sep 2020 15:42:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598974954; bh=hEcf91JbzgPXRuztevJtJxtp78NU32tVPVA7ZRUoHnU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=REPgVan5/Q6Rt1Oq2idcuIrKb4w5nba6deQdQXHzhMO+s6skHdRD47/9OZ176YHQc pvhthVi37NyLxw7wWFPFvyxWS5Qhm0rDPT+3Puw3eUEbfml6ARtPk4EWfxpTNuTNGK z98qu/dpcu2oWVNxUhWoDgbH5o/u2e6We7D+muPw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Anthony Koo , Aric Cyr , Qingqing Zhuo , Alex Deucher , Sasha Levin Subject: [PATCH 5.8 124/255] drm/amd/display: Fix LFC multiplier changing erratically Date: Tue, 1 Sep 2020 17:09:40 +0200 Message-Id: <20200901151006.670575737@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200901151000.800754757@linuxfoundation.org> References: <20200901151000.800754757@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Anthony Koo [ Upstream commit e4ed4dbbc8383d42a197da8fe7ca6434b0f14def ] [Why] 1. There is a calculation that is using frame_time_in_us instead of last_render_time_in_us to calculate whether choosing an LFC multiplier would cause the inserted frame duration to be outside of range. 2. We do not handle unsigned integer subtraction correctly and it underflows to a really large value, which causes some logic errors. [How] 1. Fix logic to calculate 'within range' using last_render_time_in_us 2. Split out delta_from_mid_point_delta_in_us calculation to ensure we don't underflow and wrap around Signed-off-by: Anthony Koo Reviewed-by: Aric Cyr Acked-by: Qingqing Zhuo Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- .../amd/display/modules/freesync/freesync.c | 36 +++++++++++++++---- 1 file changed, 29 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c index eb7421e83b865..23a7fa8447e24 100644 --- a/drivers/gpu/drm/amd/display/modules/freesync/freesync.c +++ b/drivers/gpu/drm/amd/display/modules/freesync/freesync.c @@ -324,22 +324,44 @@ static void apply_below_the_range(struct core_freesync *core_freesync, /* Choose number of frames to insert based on how close it * can get to the mid point of the variable range. + * - Delta for CEIL: delta_from_mid_point_in_us_1 + * - Delta for FLOOR: delta_from_mid_point_in_us_2 */ - if ((frame_time_in_us / mid_point_frames_ceil) > in_out_vrr->min_duration_in_us && - (delta_from_mid_point_in_us_1 < delta_from_mid_point_in_us_2 || - mid_point_frames_floor < 2)) { + if ((last_render_time_in_us / mid_point_frames_ceil) < in_out_vrr->min_duration_in_us) { + /* Check for out of range. + * If using CEIL produces a value that is out of range, + * then we are forced to use FLOOR. + */ + frames_to_insert = mid_point_frames_floor; + } else if (mid_point_frames_floor < 2) { + /* Check if FLOOR would result in non-LFC. In this case + * choose to use CEIL + */ + frames_to_insert = mid_point_frames_ceil; + } else if (delta_from_mid_point_in_us_1 < delta_from_mid_point_in_us_2) { + /* If choosing CEIL results in a frame duration that is + * closer to the mid point of the range. + * Choose CEIL + */ frames_to_insert = mid_point_frames_ceil; - delta_from_mid_point_delta_in_us = delta_from_mid_point_in_us_2 - - delta_from_mid_point_in_us_1; } else { + /* If choosing FLOOR results in a frame duration that is + * closer to the mid point of the range. + * Choose FLOOR + */ frames_to_insert = mid_point_frames_floor; - delta_from_mid_point_delta_in_us = delta_from_mid_point_in_us_1 - - delta_from_mid_point_in_us_2; } /* Prefer current frame multiplier when BTR is enabled unless it drifts * too far from the midpoint */ + if (delta_from_mid_point_in_us_1 < delta_from_mid_point_in_us_2) { + delta_from_mid_point_delta_in_us = delta_from_mid_point_in_us_2 - + delta_from_mid_point_in_us_1; + } else { + delta_from_mid_point_delta_in_us = delta_from_mid_point_in_us_1 - + delta_from_mid_point_in_us_2; + } if (in_out_vrr->btr.frames_to_insert != 0 && delta_from_mid_point_delta_in_us < BTR_DRIFT_MARGIN) { if (((last_render_time_in_us / in_out_vrr->btr.frames_to_insert) < -- 2.25.1