From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Renninger Subject: Re: Thermal kernel events API to userspace - Was: Re: thermal: Avoid CONFIG_NET compile dependency Date: Tue, 25 Jan 2011 11:12:28 +0100 Message-ID: <201101251112.28340.trenn@suse.de> References: <20110124160747.GD6424@khazad-dum.debian.net> <1295942269.1866.1201.camel@rui> Mime-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from cantor.suse.de ([195.135.220.2]:34561 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752354Ab1AYKMc (ORCPT ); Tue, 25 Jan 2011 05:12:32 -0500 In-Reply-To: <1295942269.1866.1201.camel@rui> Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Zhang Rui Cc: Henrique de Moraes Holschuh , "R, Durgadoss" , "jdelvare@novell.com" , Len Brown , "linux-acpi@vger.kernel.org" , Kay Sievers , "linux-perf-users@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-trace-users@vger.kernel.org" On Tuesday, January 25, 2011 08:57:49 AM Zhang Rui wrote: > On Tue, 2011-01-25 at 00:07 +0800, Henrique de Moraes Holschuh wrote: > > On Mon, 24 Jan 2011, Thomas Renninger wrote: > > > I wonder whether netlink is the way to go for thermal > > > events at all. > > > Sending an udev event would already contain the sysfs > > > path to the thermal device. A variable which thermal event > > > got thrown could get added and userspace can read out the rest > > > easily from sysfs files. But I expect udev is not intended > > > for such general events? > > > > udev is heavyweight in the userspace side, we'd be much better off using the > > ACPI event interface (which is netlink), or a new one to deliver system > > status events, instead of continously abusing udev for this stuff. > > > > > > > Also, the thermal_aux0 and _aux1, we can use the final format specified by you. > > > > > enum events { > > > > > THERMAL_CRITICAL, > > > > > /* user defined thermal events */ > > > > > THERMAL_USER_AUX0, > > > > > THERMAL_USER_AUX1, > > > > > THERMAL_DEV_FAULT, > > > > > }; > > > > Please give us at least two levels of thermal alarm: critical and emergency > > (or warning and critical -- it doesn't matter much, as long as there are at > > least two levels, and which one comes first is defined by the > > specification). I'd have immediate use for them on thinkpads. What kind of thinkpad specific events are these and what actions should be taken if they happen? > > It is probably best to have three levels (warning, critical, emergency). > > Best not to tie the API/ABI to the notion of "too hot", one can also alarm > > when it starts to get to cold. > > > when it's the "too hot" case, what kind of action should be taken upon > the warning/critical/emergency events? > I mean what's the difference between these three levels. I could imagine there is quite some HW out there with quite different thermal events. What other actions userspace would take beside logging the event, telling the user that a fan is switched on, CPU or whatever device gets throttled. Logging such specific info can only be implemented in the driver itself and would get lost when exporting things through a generic thermal interface. I wonder which events would need userspace to take specific (configured) actions at all and what kind of action it could be. What is THERMAL_USER_AUX0? When will it get thrown and what is userspace expected to do? Thomas