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,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 67A1FC433E0 for ; Thu, 18 Jun 2020 01:41:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 42D9022208 for ; Thu, 18 Jun 2020 01:41:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592444513; bh=bhWI4KqoyEablLasAkA2NaIXdSSmV56ucblPw/5zqLc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=0oxef2PMup5gYIcY64PfjFq22XFYAZyWWMPk2T3PJMXhp9LSMYrvdLOuVbz3lIit4 tO3JiZDC7jvyEFReyEAE2OhmqHQ63c6USnRQmliCfjRBPUdvmZw3x61gszO1Driq9q nYBZeotNker/Dnqy6L7AiKFyGS8nDVgBpbN+Tzwo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730490AbgFRB3f (ORCPT ); Wed, 17 Jun 2020 21:29:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:33892 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731034AbgFRB00 (ORCPT ); Wed, 17 Jun 2020 21:26:26 -0400 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 E0DBC2088E; Thu, 18 Jun 2020 01:26:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592443585; bh=bhWI4KqoyEablLasAkA2NaIXdSSmV56ucblPw/5zqLc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wGGE25+6OIaRka4SMetWEpS6ji2W3Ht+7i+a+Ob9bOve5fdCuZngSeNLJa81J9C16 EMmcuVb1STdbl92fr27hUWuPoeeqlkKHhWhZq+JEY8/VWPuaHP6MY2uno9AovszUbm Stq69PyN82d22REQG/q/vMGV2QZl94E0cTUcYWW8= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: =?UTF-8?q?Pali=20Roh=C3=A1r?= , Tomasz Maciej Nowak , Lorenzo Pieralisi , Rob Herring , Thomas Petazzoni , Sasha Levin , linux-pci@vger.kernel.org Subject: [PATCH AUTOSEL 4.14 020/108] PCI: aardvark: Don't blindly enable ASPM L0s and don't write to read-only register Date: Wed, 17 Jun 2020 21:24:32 -0400 Message-Id: <20200618012600.608744-20-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200618012600.608744-1-sashal@kernel.org> References: <20200618012600.608744-1-sashal@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Pali Rohár [ Upstream commit 90c6cb4a355e7befcb557d217d1d8b8bd5875a05 ] Trying to change Link Status register does not have any effect as this is a read-only register. Trying to overwrite bits for Negotiated Link Width does not make sense. In future proper change of link width can be done via Lane Count Select bits in PCIe Control 0 register. Trying to unconditionally enable ASPM L0s via ASPM Control bits in Link Control register is wrong. There should be at least some detection if endpoint supports L0s as isn't mandatory. Moreover ASPM Control bits in Link Control register are controlled by pcie/aspm.c code which sets it according to system ASPM settings, immediately after aardvark driver probes. So setting these bits by aardvark driver has no long running effect. Remove code which touches ASPM L0s bits from this driver and let kernel's ASPM implementation to set ASPM state properly. Some users are reporting issues that this code is problematic for some Intel wifi cards and removing it fixes them, see e.g.: https://bugzilla.kernel.org/show_bug.cgi?id=196339 If problems with Intel wifi cards occur even after this commit, then pcie/aspm.c code could be modified / hooked to not enable ASPM L0s state for affected problematic cards. Link: https://lore.kernel.org/r/20200430080625.26070-3-pali@kernel.org Tested-by: Tomasz Maciej Nowak Signed-off-by: Pali Rohár Signed-off-by: Lorenzo Pieralisi Acked-by: Rob Herring Acked-by: Thomas Petazzoni Signed-off-by: Sasha Levin --- drivers/pci/host/pci-aardvark.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/pci/host/pci-aardvark.c b/drivers/pci/host/pci-aardvark.c index 5f3048e75bec..c1db09fbbe04 100644 --- a/drivers/pci/host/pci-aardvark.c +++ b/drivers/pci/host/pci-aardvark.c @@ -365,10 +365,6 @@ static void advk_pcie_setup_hw(struct advk_pcie *pcie) advk_pcie_wait_for_link(pcie); - reg = PCIE_CORE_LINK_L0S_ENTRY | - (1 << PCIE_CORE_LINK_WIDTH_SHIFT); - advk_writel(pcie, reg, PCIE_CORE_LINK_CTRL_STAT_REG); - reg = advk_readl(pcie, PCIE_CORE_CMD_STATUS_REG); reg |= PCIE_CORE_CMD_MEM_ACCESS_EN | PCIE_CORE_CMD_IO_ACCESS_EN | -- 2.25.1