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=-6.0 required=3.0 tests=BAYES_00,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 EA1D4C2D0E4 for ; Tue, 17 Nov 2020 16:38:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9ADA521D7E for ; Tue, 17 Nov 2020 16:38:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="FJgl0tcR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727265AbgKQQiT (ORCPT ); Tue, 17 Nov 2020 11:38:19 -0500 Received: from mail.kernel.org ([198.145.29.99]:60164 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727010AbgKQQiT (ORCPT ); Tue, 17 Nov 2020 11:38:19 -0500 Received: from localhost (189.sub-72-105-114.myvzw.com [72.105.114.189]) (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 BA0A2217A0; Tue, 17 Nov 2020 16:38:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605631099; bh=2Bs/+9brtdJ8Qim1oOERf9SEfxCTiMSLLDSQGAmSgVw=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=FJgl0tcRT6TKxDjmnER5PUVWbYUBtf3WNlJCooBmiNQC7EPHXuFU+gsfAWh5vcer9 SvDxb90pgHzn/bVoIC+qV0f2WK9Z/lkKZOHEIA8qp3ySR7OJ8+VEgM0no0+sZ/zv5o 9q6GVtsUygiaMPLli/873XLwhSKeFJZF5lX+eQ5c= Date: Tue, 17 Nov 2020 10:38:17 -0600 From: Bjorn Helgaas To: Heiner Kallweit , "Rafael J. Wysocki" Cc: Bjorn Helgaas , Mika Westerberg , Kai Heng Feng , Lukas Wunner , "linux-pci@vger.kernel.org" , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: Time to re-enable Runtime PM per default for PCI devcies? Message-ID: <20201117163817.GA1397220@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <79940973-b631-90f9-dbc4-9579c6000816@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org [+to Rafael, author of the commit you mentioned, +cc Mika, Kai Heng, Lukas, linux-pm, linux-kernel] On Tue, Nov 17, 2020 at 04:56:09PM +0100, Heiner Kallweit wrote: > More than 10 yrs ago Runtime PM was disabled per default by bb910a7040 > ("PCI/PM Runtime: Make runtime PM of PCI devices inactive by default"). > > Reason given: "avoid breakage on systems where ACPI-based wake-up is > known to fail for some devices" > Unfortunately the commit message doesn't mention any affected devices > or systems. > > With Runtime PM disabled e.g. the PHY on network devices may remain > powered up even with no cable plugged in, affecting battery lifetime > on mobile devices. Currently we have to rely on the respective distro > or user to enable Runtime PM via sysfs (echo auto > power/control). > Some devices work around this restriction by calling pm_runtime_allow > in their probe routine, even though that's not recommended by > https://www.kernel.org/doc/Documentation/power/pci.txt > > Disabling Runtime PM per default seems to be a big hammer, a quirk > for affected devices / systems may had been better. And we still > have the option to disable Runtime PM for selected devices via sysfs. > > So, to cut a long story short: Wouldn't it be time to remove this > restriction? I don't know the history of this, but maybe Rafael or the others can shed some light on it.