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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 7B6DEC433DF for ; Mon, 1 Jun 2020 15:13:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 46849207DF for ; Mon, 1 Jun 2020 15:13:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591024422; bh=xCkd2fICeOT9Ubja+5vo62mABuxHHRilmgEk9G4WHwk=; h=Date:From:To:Cc:Subject:In-Reply-To:List-ID:From; b=M6xussbP07MYn8ax7Pz8zgukUcnTvcDbNwHCdat0iDdZ9Ada/bzQ7qtTqi5gNIP4w 0wTrcerKHbde6qtaxIVpfQn2GzF9g5hvr+45u7R/UZORREtRoALyNjeWWoT0MMODwJ OY5RmcNb7QgqO+8OcrVWy9Ith+MhX4xQDzJvKxnA= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726075AbgFAPNl (ORCPT ); Mon, 1 Jun 2020 11:13:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:38854 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726017AbgFAPNl (ORCPT ); Mon, 1 Jun 2020 11:13:41 -0400 Received: from localhost (mobile-166-175-190-200.mycingular.net [166.175.190.200]) (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 A431C20738; Mon, 1 Jun 2020 15:13:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591024421; bh=xCkd2fICeOT9Ubja+5vo62mABuxHHRilmgEk9G4WHwk=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=EYDb/OHT+pWpoo4RcVx+H1fEMIm5fhsJZ7hQWUeU4Gg1D4EDLU+t796v8MXUvc/pc uAgIgKYINjVWVd/mL3SqvTGJq1nI4p8g+gtpqxYjCTBkMeOmK5eGHsnyGMMbiwQcm3 s3mE945pSdBwHTqRlXBUdPO9CAJNcov8kUS7E4EM= Date: Mon, 1 Jun 2020 10:13:39 -0500 From: Bjorn Helgaas To: Christoph Hellwig Cc: Matthew Garrett , Heiner Kallweit , Bjorn Helgaas , "Rafael J. Wysocki" , "linux-pci@vger.kernel.org" , linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org Subject: Re: Lost PCIe PME after a914ff2d78ce ("PCI/ASPM: Don't select CONFIG_PCIEASPM by default") Message-ID: <20200530123421.GA532471@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200530113344.GA2834@infradead.org> Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On Sat, May 30, 2020 at 04:33:44AM -0700, Christoph Hellwig wrote: > On Sat, May 30, 2020 at 08:14:34AM +0100, Matthew Garrett wrote: > > On Sat, May 30, 2020 at 08:33:50AM +0200, Heiner Kallweit wrote: > > > > > It *was* default y. This changed with a914ff2d78ce ("PCI/ASPM: Don't > > > select CONFIG_PCIEASPM by default") and that's what triggered the > > > problem. If there's no easy solution, then maybe it's best to revert > > > the change for now. > > > > Oh, sorry, I was looking at mainline. CONFIG_PCIEASPM should > > *definitely* be enabled by default - platforms expect the OS to support > > it. If we want to get rid of default y then I think it'd make more sense > > to have a CONFIG_DISABLE_PCIEASPM that's under EXPERT, and people who > > really want to disable the code can do so. > > I think the fact that the EXPERT didn't get removed in the above bug > is a defintive bug. But I'd go further and think the CONFIG_PCIEASPM > option should be removed entirely. There is absolutely no good reason > to not build this small amount of code if PCIe support is enabled. That might be a good solution. I don't really want a situation where leaving CONFIG_PCIEASPM unset is "known to break PME." ASPM support has historically been fragile, and it's actually a significant amount of code (~10KB on my x86), which is larger than many other things for which we have config options. But we do have boot-time and run-time ways to disable it. Another possibility might be to make it so Linux always advertises ASPM support, but doesn't actually *do* anything unless CONFIG_PCIEASPM is set. I don't think advertising ASPM support means the OS is required to change whatever configuration firmware did. Bjorn