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[209.132.180.67]) by mx.google.com with ESMTP id f3si11015074ejb.49.2019.11.04.05.54.15; Mon, 04 Nov 2019 05:54:39 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728793AbfKDNvR (ORCPT + 99 others); Mon, 4 Nov 2019 08:51:17 -0500 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:46229 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727663AbfKDNvR (ORCPT ); Mon, 4 Nov 2019 08:51:17 -0500 Received: from callcc.thunk.org (ip-12-2-52-196.nyc.us.northamericancoax.com [196.52.2.12]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id xA4DpDoC017133 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 4 Nov 2019 08:51:14 -0500 Received: by callcc.thunk.org (Postfix, from userid 15806) id 6E649420311; Mon, 4 Nov 2019 08:51:11 -0500 (EST) Date: Mon, 4 Nov 2019 08:51:11 -0500 From: "Theodore Y. Ts'o" To: Tom Cook Cc: linux-kernel@vger.kernel.org Subject: Re: Power management - HP 15-ds0502na Message-ID: <20191104135111.GF28764@mit.edu> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 04, 2019 at 11:21:24AM +0000, Tom Cook wrote: > * Power management doesn't work very well. The most obvious symptom > of this is that /sys/power/mem_sleep contains only "[s2idle]" and so > there is no suspend-to-RAM available. Setting > "mem_sleep_default=deep" on the command line doesn't change this. This is actually the laptop's ACPI and/or EC not supporting suspend-to-ram at all. Suspend to idle is the new hotness, because it gives the OS much more control (but also gives the OS much more opportunity to screw up). The Dell XPS 13 (models 9370 and 9380) supports both s2idle and s2ram, but s2idle doesn't work well at all on Linux. (Well, at least not the upstream kernels; the official Dell Ubuntu kernel and userspace apparently has enough tweaks that it works well.) I tried for a bit to see if I could get s2idle working well on the upstream Dell XPS 13, but bits of hardware would randomly fail to come back from a s2idle resume --- or in some cases, the laptop wouldn't come back at all, that I decided, "life's too short", and gave up on it. Hopefully Dell or other folks will get s2idle working well on the XPS 13... at least before suspend2ram gets dropped entirely. :-/ > * There are a few devices that appear to be on I2C buses and declared > in the ACPI tables (eg the fingerprint sensor) which don't show up > under Linux. They did under Windows, until I blew the Windows > installation away to install Linux, and I'm assuming that Windows > found them through the ACPI DSDT. Now thinking it may have been handy > to keep Windows around for debugging, but that's regrets for you. Even if they showed up, it's unclear the device driver would exist for Linux. Most fingerprint readers have proprietary interfaces and aren't well supported by Linux in general. > Is this the right place to raise this? If there's some other place > that Linux ACPI issues are dealt with, please point me there as I've > not had any luck googling. There is the linux-acpi@vger.kernel.org mailing list and the linux-pm@vger.kernel.org (pm --> "power management") where you might try asking about the s2idle. A lot of the issues with s2idle appear to be very device driver specific, and not about the power management core, so it's unclear folks on those lists will be able to help. But it's worth a try... - Ted