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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 41CEFC33CAF for ; Thu, 16 Jan 2020 17:13:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 15AF2246A8 for ; Thu, 16 Jan 2020 17:13:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579194783; bh=y0+WgApjunz0Ef6HurVOOELfgTPbItrrD/zs2yt9JIo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=W5BUkFyV9dmeNae174UikG6cw4jBGPR/3xiqzX6SbplYRPopfa7sYcUmO6Fi7Vrpe R38vBwh5CINHmTeE7s0isnEXEcie1qu30d/SlqV4HTw88VmUlMWqMWLlo9wnMDcBmv NGtZ9kIBV16V5NdleKSPepUwgm00pLhYrMITrBVI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732131AbgAPRNB (ORCPT ); Thu, 16 Jan 2020 12:13:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:56828 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390622AbgAPRM7 (ORCPT ); Thu, 16 Jan 2020 12:12:59 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 88F862469A; Thu, 16 Jan 2020 17:12:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579194778; bh=y0+WgApjunz0Ef6HurVOOELfgTPbItrrD/zs2yt9JIo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZAH/Yz/pFCwueM1hBiH+Y9GdCvD/t82fcoUlTz4kg4h9TeVGcAN10wvAwe+2X01i+ b6t5KF5/bWMkseZBSPHiPN9CxYNFoqTQB65hO4wFh7FXqTPIlVzR41GXRWr+4tdVxQ pQdL7lmE5E+haWBjOTWq1aJ21HxkcUqgieVrHhlY= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jeffrey Hugo , Hai Li , Rob Clark , Sean Paul , Sean Paul , Sasha Levin , linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org Subject: [PATCH AUTOSEL 4.19 595/671] drm/msm/dsi: Implement reset correctly Date: Thu, 16 Jan 2020 12:03:53 -0500 Message-Id: <20200116170509.12787-332-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200116170509.12787-1-sashal@kernel.org> References: <20200116170509.12787-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@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 cc4ea5502d6c..3b78bca0bb4d 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