From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S940764AbdDTD4P (ORCPT ); Wed, 19 Apr 2017 23:56:15 -0400 Received: from mail.kernel.org ([198.145.29.136]:40146 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S940366AbdDTD4M (ORCPT ); Wed, 19 Apr 2017 23:56:12 -0400 MIME-Version: 1.0 In-Reply-To: <20170420030959.GC23085@kernel.dk> References: <20170420030959.GC23085@kernel.dk> From: Andy Lutomirski Date: Wed, 19 Apr 2017 20:55:47 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 0/5] nvme APST fixes/improvements for 4.11 To: Jens Axboe Cc: Andy Lutomirski , "linux-kernel@vger.kernel.org" , Kai-Heng Feng , linux-nvme , Christoph Hellwig , Sagi Grimberg , Keith Busch Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 19, 2017 at 8:10 PM, Jens Axboe wrote: > On Wed, Apr 19 2017, Andy Lutomirski wrote: >> Sorry for waiting so long for this. I was waiting for feedback from >> Samsung, but they haven't root-caused the issue yet, and I should >> have just done this from the beginning. >> >> This series makes APST more debuggable and updates the quirk list. >> The quirks I'm aware of are: >> >> - Samsung 950 series SSDs in Dell XPS 15 9550 and Precision 5510 >> laptops (which are essentially the same laptop) can lose their >> PCIe link if they're allowed to use the deepest APST state. >> Samsung engineers have an affected system and are working on >> it. The same exact SSDs in other machines (even an XPS 13) >> seem to work fine. >> >> - One Toshiba device malfunctions if APST is used at all. > > You need to split this series in two, patches 1-3 can wait. For 4.11, > all we need to do is turn off APST on any device that potentially has > this problem. > >> One thing that improves my confidence that there aren't too many >> more problems with APST is that Ubuntu has backported APST to Zesty, >> so it's already gotten a bit of testing in a widely used (if very >> new) release. > > Honestly, I think the best path for 4.11 is to turn off APST by default, > make it opt-in instead. I don't share your optimism here, as I made > clear back from before we even merged this feature. > > I can make it so that force_apst=0 means no APST and force_apst=1 mean yes APST and we could try again with a quirk list for 4.12. There's a decent chance that a few more weeks with Ubuntu having APST on will shake out all the problems fairly quickly. --Andy