From patchwork Fri Apr 24 15:38:48 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Pali_Roh=C3=A1r?= X-Patchwork-Id: 1276450 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=default header.b=zOfcjEtz; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 497yyl4X04z9sV4 for ; Sat, 25 Apr 2020 01:39:27 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728563AbgDXPjW (ORCPT ); Fri, 24 Apr 2020 11:39:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:36486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728464AbgDXPjQ (ORCPT ); Fri, 24 Apr 2020 11:39:16 -0400 Received: from pali.im (pali.im [31.31.79.79]) (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 7AD0320706; Fri, 24 Apr 2020 15:39:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587742755; bh=7Q6yx7BAcNGphXyMJ64Hizlmq02sPIkiGXe5IfpE7Z8=; h=From:To:Subject:Date:In-Reply-To:References:From; b=zOfcjEtzZDdJPDC6Pu/dUsj0Z6/XOyHEFjq2DuKTHjfNUOhcvRW7jYI4u6l8wrq6B kh7uTzdQgThIeo2WK/c3sNVdxqKrbU1rM67PGcuRhtTsa+yoY4EGvqT0+u83UUOA2X z3qpMiFXXrvpCsLPulMIsI7U1IsiE36TwC2SeB2Y= Received: by pali.im (Postfix) id 93D25A05; Fri, 24 Apr 2020 17:39:13 +0200 (CEST) From: =?utf-8?q?Pali_Roh=C3=A1r?= To: linux-pci@vger.kernel.org, Jason Cooper , Andrew Lunn , Gregory Clement , Sebastian Hesselbarth , Thomas Petazzoni , Lorenzo Pieralisi , Andrew Murray , Remi Pommarel , Tomasz Maciej Nowak , Xogium , Rob Herring , =?utf-8?q?Marek_?= =?utf-8?q?Beh=C3=BAn?= , Bjorn Helgaas Subject: [PATCH v3 02/12] PCI: aardvark: Don't blindly enable ASPM L0s and don't write to read-only register Date: Fri, 24 Apr 2020 17:38:48 +0200 Message-Id: <20200424153858.29744-3-pali@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200424153858.29744-1-pali@kernel.org> References: <20200424153858.29744-1-pali@kernel.org> MIME-Version: 1.0 Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org 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. Signed-off-by: Pali Rohár --- 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 f9955b494267..74b90940a9d4 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -356,10 +356,6 @@ 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 |