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=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 88F1DC433DF for ; Thu, 18 Jun 2020 02:05:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 69C652220B for ; Thu, 18 Jun 2020 02:05:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592445902; bh=ptpv6AaHe3Ar61d8PWH8ycxxaQqCbcDaY5LkOUNJEmI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=w/oWSAzaGagUK5RFxssMZsZivJbJiibBWCDJlprxnNrGOOZugsElsi3SFZPBagAVu O8hhzAtVvH3SVWUzYDgy7uvXHLO6S8PJxzYE59/EeEkEbSB11SvYcfstmECfOTmZGx sL0aGrIc+MyUwQ6Kq8NvGoHtcBsY6Y6WSHlyV2Sc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730882AbgFRCFA (ORCPT ); Wed, 17 Jun 2020 22:05:00 -0400 Received: from mail.kernel.org ([198.145.29.99]:56112 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730367AbgFRBWx (ORCPT ); Wed, 17 Jun 2020 21:22:53 -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 44B9B20663; Thu, 18 Jun 2020 01:22:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592443373; bh=ptpv6AaHe3Ar61d8PWH8ycxxaQqCbcDaY5LkOUNJEmI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=tvsEWH/GXosw17DHT7zf6Rt6Gd2qjIh8yvLXdn+HOBiyZylzr8V3e7PmFIeMUk4mb hxQI+4XZ9O/8I3rQaNFhabFk46B0qTwKxVu9JBPq2LkebuUwn1+T6v9+Sa4SPOkW0S ojnejE6wheRLsoRNVqRjeqVA9NoAxNvIzPx+fEfM= 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, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 4.19 026/172] PCI: aardvark: Don't blindly enable ASPM L0s and don't write to read-only register Date: Wed, 17 Jun 2020 21:19:52 -0400 Message-Id: <20200618012218.607130-26-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200618012218.607130-1-sashal@kernel.org> References: <20200618012218.607130-1-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/controller/pci-aardvark.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index 6b4555ff2548..0235b6e7dcd1 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -321,10 +321,6 @@ 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