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 78F37C433F5 for ; Sat, 23 Apr 2022 05:49:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233444AbiDWFwu (ORCPT ); Sat, 23 Apr 2022 01:52:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46146 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233500AbiDWFwi (ORCPT ); Sat, 23 Apr 2022 01:52:38 -0400 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BDE6923E3E4 for ; Fri, 22 Apr 2022 22:49:42 -0700 (PDT) Received: by verein.lst.de (Postfix, from userid 2407) id 5A9EE68AFE; Sat, 23 Apr 2022 07:49:38 +0200 (CEST) Date: Sat, 23 Apr 2022 07:49:38 +0200 From: Christoph Hellwig To: Manivannan Sadhasivam Cc: hch@lst.de, linux-nvme@lists.infradead.org, sagi@grimberg.me, Rafael Wysocki , Vidya Sagar , kbusch@kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH] nvme/pci: default to simple suspend Message-ID: <20220423054938.GA17945@lst.de> References: <20220201165006.3074615-1-kbusch@kernel.org> <20220411135850.GA42637@thinkpad> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220411135850.GA42637@thinkpad> User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, Apr 11, 2022 at 07:28:50PM +0530, Manivannan Sadhasivam wrote: > PCI core only accepts the quirks for the host devices that could be passed onto > the PCI device drivers like this one. In this case, this is not a quirk but > actually an aggressive power saving feature (atleast on the Qcom platforms). > Moreover, adding a flag to the PCI bus will make it applicable to all the > child devices of the RC/bridge and that would be wrong. As you correctly state it is not a device quirk. It describes the power management applied by the platform. So we do need to communicate it through the core PM and/or PCI code. Please work with the relevant maintainers. > In our case, the same power saving feature is not applicable to all PCI devices > like WLAN for an example. This doesn't make sense. Your plaform can't know what device is connected to a given root port / slot. So you might have different policies per slot, but that has nothing to do with the Linux drivers for given devices.