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=-10.0 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,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 BFA9CC433DF for ; Tue, 23 Jun 2020 20:44:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9D10E21D6C for ; Tue, 23 Jun 2020 20:44:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592945059; bh=nfBpttPTgdjEcAGwZzBdAE0VsG6wpa3cWqoOnuqOev0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=v33cf5TqI6WeeUeWPfwaKSCzQapCYPY+y8Teyzznb8WGRd6hHNlkUpIUONKitSHOp 7z52t8z9Awa/tUnaUm+57bv2wn55VVqDXhlvmHSi0xEny7ig4x4whhXGezqiGRPZph QudZICNXJx7Cnd34yUkO2T9Nw3sBxIqw6fj9taeU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403986AbgFWUoR (ORCPT ); Tue, 23 Jun 2020 16:44:17 -0400 Received: from mail.kernel.org ([198.145.29.99]:41278 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2403978AbgFWUoM (ORCPT ); Tue, 23 Jun 2020 16:44:12 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 B22F321BE5; Tue, 23 Jun 2020 20:44:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592945052; bh=nfBpttPTgdjEcAGwZzBdAE0VsG6wpa3cWqoOnuqOev0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yk94XXjJB7cXcPV0Qruw3PHzj4R6y3u5yrAqPtt74QxPopGbB9adgQ0StaXedCZe3 nxwjCn74HGy1apvEWL6niLHEdStnYmbO9D065LUEcX5I6p66CVWlqBtWdHzdPzxExe LwUcoHoREoGJhGX06J9053OxvKioLVHt7JN0WNXo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tomasz Maciej Nowak , =?UTF-8?q?Pali=20Roh=C3=A1r?= , Lorenzo Pieralisi , Rob Herring , Thomas Petazzoni , Sasha Levin Subject: [PATCH 4.14 020/136] PCI: aardvark: Dont blindly enable ASPM L0s and dont write to read-only register Date: Tue, 23 Jun 2020 21:57:56 +0200 Message-Id: <20200623195304.629278646@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200623195303.601828702@linuxfoundation.org> References: <20200623195303.601828702@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: 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 5f3048e75becb..c1db09fbbe041 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