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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D4C13C433EF for ; Sat, 23 Apr 2022 05:49:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=gLjiVH8iNH5jUt9ousb2g6gL91YM6+MV1JHdczVHJS0=; b=ET86eqME0gbxnFZ8i/xa8X55KM Bdb6HvhDlqnPwuy2mazpwCTx5q9VN8FvKaWdnH7AueUwgrrsunvxYRQShdRJ5SV0NY5cl8cv4Wefg +MsIUluTQ2IWPPpsFGrgG7eqbfXzAtyNazNxke72p09Zzyb59GbdgtL1b0VH0WfngY5eSj9U4OLBd ylqtx10mozk89s3V94/gUm4S/XlDtJni0lONi+OASUFhwU9ve7XlR7dLZZj+DUs7siX9d/8KdPjDq BlzRwsinqxGgPB1BFhRmJvY6rbOAIk+EsFe9KFsby2bNtVrB94jiYojfEzHGFOVm8hvyIdzgi9f1x CfiAvYSA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ni8eP-003WSu-3f; Sat, 23 Apr 2022 05:49:45 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ni8eM-003WSS-NS for linux-nvme@lists.infradead.org; Sat, 23 Apr 2022 05:49:44 +0000 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) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220422_224942_951514_A7CC512A X-CRM114-Status: GOOD ( 16.57 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.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.