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 52BC1C433FE for ; Wed, 16 Feb 2022 17:13:01 +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=Z6ZkAKcGAc8HyB5DxrQiZvs7DK8Ja5ViwJAo9ydHrpY=; b=TDpT1dBlscB0G/f0TtTRTByB1W qZtSEEl9S5ltv6JAsiwEAd58YDqlEE++hb56h/5jqf8Bv33rtADpwtria2jKcERjQvflJ3zgxOYpY 6aKNWtx8/KVzEKa0WnzaMP+M04md6CWIUoIXox6Lac4eduHeogTk+LtBGBDfdIvt/fEysMVr2hPkz fPJcXhgcZGpjOOAP6V53mULtnG3Uatw1ajVmumPEAowi8Yepkc0AoTsK3o9ABAFL7IoQyPCMyr5ry +hBE5Uerl8WJ8exVQTM3QyQR7ZY34wxZvGkT80IPIQcnhhNQc/QUX5Cw0Nofly/38pdVfjahHocKD AX2sWemA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nKNrN-007ryW-JX; Wed, 16 Feb 2022 17:12:57 +0000 Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nKNrG-007rwX-6k; Wed, 16 Feb 2022 17:12:50 +0000 Date: Wed, 16 Feb 2022 09:12:50 -0800 From: Christoph Hellwig To: "Nitin Rawat (QUIC)" Cc: Christoph Hellwig , Vidya Sagar , Keith Busch , Jens Axboe , Sagi Grimberg , "linux-nvme@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "Sajida Bhanu (Temp) (QUIC)" Subject: Re: [PATCH v3] nvme/pci: Add quick suspend quirk for Sc7280 Platform Message-ID: References: <1644526408-10834-1-git-send-email-quic_nitirawa@quicinc.com> <9b291987cf914f119788c42b32a08a12@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9b291987cf914f119788c42b32a08a12@quicinc.com> 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 Wed, Feb 16, 2022 at 04:07:05PM +0000, Nitin Rawat (QUIC) wrote: > Hi Christoph/Keith/Rafael > > Since we are giving control to PCIe (NVMe power rails control), it can vary from platform to platform. > More over, PCIe driver doesn't control these power rails directly from PCIe driver, they tie nvme supply with one of the pcie supply and control them together. > So i think it would be better to either have quirk based on platform or always setting simple suspend and platform which needs full suspend can update it through some means. > > Based on below link, Looks like this can be across platform ...vidya also mention similar concern for tegra platform. Here is the thing: nothing here is really NVMe specific. We do have a bunch of drivers including nvme that would love to not do a full firmware shutdown on a suspend. For storage devices this is especially important as each shutdown reduces media life time. Until very recently this has been perfectly fine, but now various platforms show up that want to completely disable power to PCIe slots on a system suspend. The drivers need information from the PCI / PM core when a ->suspend call requires the device to got into D3 and when not, and we can't just do that with quirks in the various drivers.