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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,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 73DBEC2D0DB for ; Fri, 24 Jan 2020 11:35:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3CA372077C for ; Fri, 24 Jan 2020 11:35:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579865714; bh=WuRajSslgg9FwxSUgUQ7vxI+yxTOYwbR9hLen+p2fYo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=YD184xqtigJIxnlPwqXv3tfHbfBtmXZgvkdGeZ1JX3T13tYQt7uXMzscAGYtaUa4S DRy4ixRwj8Ch9LHH7k/5W50IKHRRLjDlOH4595v6brMbtyz2P9kVaGAu9lAhUta8re SJ2kyaUex78oslzoDDCoyiUWj5qOuMoq6o1yqvWI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404815AbgAXLfN (ORCPT ); Fri, 24 Jan 2020 06:35:13 -0500 Received: from mail.kernel.org ([198.145.29.99]:55150 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404631AbgAXLfK (ORCPT ); Fri, 24 Jan 2020 06:35:10 -0500 Received: from localhost (ip-213-127-102-57.ip.prioritytelecom.net [213.127.102.57]) (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 1890B222D9; Fri, 24 Jan 2020 11:35:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579865709; bh=WuRajSslgg9FwxSUgUQ7vxI+yxTOYwbR9hLen+p2fYo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QuAPmxxGeFuwFXIyR2BvZ4Wo86aNsfciFHaDkULI1NMJ93YZKCVjhiu/8L0pIcWi/ gSPPPaUl7bUFB72iPgOk1Ys9Wo/box845l3xIVMqrkjTmDtfWrmbehVDXQn5nLU6dL /bVIYFePhkM9JAsMhP/OjM1SooIxHviXOEmFjTY4= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Hai Li , Rob Clark , Jeffrey Hugo , Sean Paul , Sean Paul , Sasha Levin Subject: [PATCH 4.19 604/639] drm/msm/dsi: Implement reset correctly Date: Fri, 24 Jan 2020 10:32:54 +0100 Message-Id: <20200124093205.109249543@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200124093047.008739095@linuxfoundation.org> References: <20200124093047.008739095@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: Jeffrey Hugo [ Upstream commit 78e31c42261779a01bc73472d0f65f15378e9de3 ] On msm8998, vblank timeouts are observed because the DSI controller is not reset properly, which ends up stalling the MDP. This is because the reset logic is not correct per the hardware documentation. The documentation states that after asserting reset, software should wait some time (no indication of how long), or poll the status register until it returns 0 before deasserting reset. wmb() is insufficient for this purpose since it just ensures ordering, not timing between writes. Since asserting and deasserting reset occurs on the same register, ordering is already guaranteed by the architecture, making the wmb extraneous. Since we would define a timeout for polling the status register to avoid a possible infinite loop, lets just use a static delay of 20 ms, since 16.666 ms is the time available to process one frame at 60 fps. Fixes: a689554ba6ed ("drm/msm: Initial add DSI connector support") Cc: Hai Li Cc: Rob Clark Signed-off-by: Jeffrey Hugo Reviewed-by: Sean Paul [seanpaul renamed RESET_DELAY to DSI_RESET_TOGGLE_DELAY_MS] Signed-off-by: Sean Paul Link: https://patchwork.freedesktop.org/patch/msgid/20191011133939.16551-1-jeffrey.l.hugo@gmail.com Signed-off-by: Sasha Levin --- drivers/gpu/drm/msm/dsi/dsi_host.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c index cc4ea5502d6c3..3b78bca0bb4d4 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_host.c +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c @@ -34,6 +34,8 @@ #include "dsi_cfg.h" #include "msm_kms.h" +#define DSI_RESET_TOGGLE_DELAY_MS 20 + static int dsi_get_version(const void __iomem *base, u32 *major, u32 *minor) { u32 ver; @@ -994,7 +996,7 @@ static void dsi_sw_reset(struct msm_dsi_host *msm_host) wmb(); /* clocks need to be enabled before reset */ dsi_write(msm_host, REG_DSI_RESET, 1); - wmb(); /* make sure reset happen */ + msleep(DSI_RESET_TOGGLE_DELAY_MS); /* make sure reset happen */ dsi_write(msm_host, REG_DSI_RESET, 0); } @@ -1402,7 +1404,7 @@ static void dsi_sw_reset_restore(struct msm_dsi_host *msm_host) /* dsi controller can only be reset while clocks are running */ dsi_write(msm_host, REG_DSI_RESET, 1); - wmb(); /* make sure reset happen */ + msleep(DSI_RESET_TOGGLE_DELAY_MS); /* make sure reset happen */ dsi_write(msm_host, REG_DSI_RESET, 0); wmb(); /* controller out of reset */ dsi_write(msm_host, REG_DSI_CTRL, data0); -- 2.20.1