Return-Path: Subject: Re: udev USB autosupend whitelist (was Re: [PATCH] Bluetooth: btusb: Restore QCA Rome suspend/resume fix with a "rewritten" version) To: Brian Norris Cc: Marcel Holtmann , Gustavo Padovan , Johan Hedberg , linux-bluetooth@vger.kernel.org, linux-serial@vger.kernel.org, linux-acpi@vger.kernel.org, stable@vger.kernel.org, Leif Liddy , Matthias Kaehlcke , Daniel Drake , Kai-Heng Feng , matadeen@qti.qualcomm.com, linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Guenter Roeck , Benson Leung References: <20180108094416.4789-1-hdegoede@redhat.com> <20180213022455.GA151190@rodete-desktop-imager.corp.google.com> <8cd918fd-bf6f-70ac-e561-e7deffa695f0@redhat.com> <20180216022721.GA69988@rodete-desktop-imager.corp.google.com> <0a13d0f3-8e0d-74df-df9c-2bf0622a9fb6@redhat.com> <20180216164924.GA72213@rodete-desktop-imager.corp.google.com> From: Hans de Goede Message-ID: <28da6a0a-cda6-82f1-9200-4a0bb30c0663@redhat.com> Date: Mon, 19 Feb 2018 15:59:42 +0100 MIME-Version: 1.0 In-Reply-To: <20180216164924.GA72213@rodete-desktop-imager.corp.google.com> Content-Type: text/plain; charset=utf-8; format=flowed List-ID: Hi, On 16-02-18 17:49, Brian Norris wrote: > + Benson (and there are probably others that know better answers) > > Hi, > > On Fri, Feb 16, 2018 at 09:26:37AM +0100, Hans de Goede wrote: >> Going a bit off-topic here, so changed the subject. >> I will reply on topic in another mail. >> >> On 16-02-18 03:27, Brian Norris wrote: >>> I use a set of udev rules that manually whitelist devices for >>> autosuspend. You can see it here: >>> >>> https://chromium.googlesource.com/chromiumos/platform2/+/43728a93f6de137006c6b92fbb2a7cc4f353c9bf/power_manager/udev/gen_autosuspend_rules.py#83 >>> >>> You'll find at least one Rome chip in there. >> >> Oh, that is a very interesting link for the work I've been doing to >> improve Linux power-consumption in general: >> >> https://fedoraproject.org/wiki/Changes/ImprovedLaptopBatteryLife >> >> I was actually planning on at least doing such a list for WWAN modems, >> for btusb my approach has been to just enable it everywhere >> (except for QCA devices as I got bugreports for those). >> >> Note that I plan to eventually submit this whitelist to the >> udev rules which are part of systemd upstream, so if chromeos >> is using systemd too, this is something to be aware of for you. > > Chrome OS does not currently use systemd, but thanks for the heads up. > >> Question, is the white-listing of the root and rate-limiting >> hubs really necessary? I thought these have this enabled by default? > > This list is old and maintained by several of my team, originating from > quite a ways back (i.e., much older kernels). It's quite possible that > some of it is redundant today. Ok, I double checked and it seems that explicitly setting power/control to auto for any USB hub is not necessary as they all default to auto now. So FWIW you may want to consider removing this. Regards, Hans