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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A46E5C38145 for ; Fri, 2 Sep 2022 23:57:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229484AbiIBX5h (ORCPT ); Fri, 2 Sep 2022 19:57:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229436AbiIBX5e (ORCPT ); Fri, 2 Sep 2022 19:57:34 -0400 Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1645DDDA9A; Fri, 2 Sep 2022 16:57:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1662163054; x=1693699054; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=6gAaOCMk8Z/d7uqTVGe/Hinra8KYs7C0oQAPXXXj8lU=; b=gURNjs14S8CgizsiKBgWglSv3CYHiRxv2Fvrzez6u/05JoXUYfc92lAc W7HPQ7ZwqshWG7pe3FD/4ED05asKvNuQZdy1nHKwDI7f+EYBnzDlp6eKj wwOquQ8dQd3gn6uEqMnbumWMGPVObdvZh3GnTuBUfZxhvoOhV86m8Ru5G +Jc89a7/0EtrUn8Bj4RrCNZxbcwRZSPogGzm8Z0X9arJNz5cwGHvYRfed bQxEwjJZp5nCPKswi4F39QIqY7IdVZhj+MNuQZ6JgkvCauUzwNV6cyqNs AIB3HjC1arbBfP7bPameCxK6crzWo4aU9xs9aCKhjW7dpTdeqdFvOpWIX w==; X-IronPort-AV: E=McAfee;i="6500,9779,10458"; a="357824977" X-IronPort-AV: E=Sophos;i="5.93,285,1654585200"; d="scan'208";a="357824977" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Sep 2022 16:57:33 -0700 X-IronPort-AV: E=Sophos;i="5.93,285,1654585200"; d="scan'208";a="755422714" Received: from cgoff-mobl1.amr.corp.intel.com (HELO [10.209.53.13]) ([10.209.53.13]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Sep 2022 16:57:33 -0700 Message-ID: <17c2cba5-fcb3-1e02-b488-65f4dafe6367@linux.intel.com> Date: Fri, 2 Sep 2022 16:57:32 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0 Thunderbird/91.11.0 Subject: Re: [PATCH v2 1/3] PCI/PTM: Preserve PTM Root Select Content-Language: en-US To: Bjorn Helgaas , Kai-Heng Feng , Rajvi Jingar , "Rafael J . Wysocki" Cc: Koba Ko , Mika Westerberg , "David E . Box" , linux-pci@vger.kernel.org, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, Bjorn Helgaas References: <20220902233543.390890-1-helgaas@kernel.org> <20220902233543.390890-2-helgaas@kernel.org> From: Sathyanarayanan Kuppuswamy In-Reply-To: <20220902233543.390890-2-helgaas@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hi, On 9/2/22 4:35 PM, Bjorn Helgaas wrote: > From: Bjorn Helgaas > > When disabling PTM, there's no need to clear the Root Select bit. We > disable PTM during suspend, and we want to re-enable it during resume. > Clearing Root Select here makes re-enabling more complicated. > > Per PCIe r6.0, sec 7.9.15.3, "When set, if the PTM Enable bit is also Set, > this Time Source is the PTM Root," so if PTM Enable is cleared, the value > of Root Select should be irrelevant. > > Preserve Root Select to simplify re-enabling PTM. > > Signed-off-by: Bjorn Helgaas > Cc: David E. Box > --- Reviewed-by: Kuppuswamy Sathyanarayanan > drivers/pci/pcie/ptm.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c > index 368a254e3124..b6a417247ce3 100644 > --- a/drivers/pci/pcie/ptm.c > +++ b/drivers/pci/pcie/ptm.c > @@ -42,7 +42,7 @@ void pci_disable_ptm(struct pci_dev *dev) > return; > > pci_read_config_word(dev, ptm + PCI_PTM_CTRL, &ctrl); > - ctrl &= ~(PCI_PTM_CTRL_ENABLE | PCI_PTM_CTRL_ROOT); > + ctrl &= ~PCI_PTM_CTRL_ENABLE; > pci_write_config_word(dev, ptm + PCI_PTM_CTRL, ctrl); > } > -- Sathyanarayanan Kuppuswamy Linux Kernel Developer