From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian Norris Subject: Re: thermal: uevent/netlink with step_wise? Date: Wed, 1 Apr 2015 14:17:18 -0700 Message-ID: <20150401211718.GA32500@ld-irv-0074> References: <20150331224348.GZ32500@ld-irv-0074> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pa0-f54.google.com ([209.85.220.54]:34209 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751149AbbDAVR2 (ORCPT ); Wed, 1 Apr 2015 17:17:28 -0400 Received: by pactp5 with SMTP id tp5so63246487pac.1 for ; Wed, 01 Apr 2015 14:17:27 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20150331224348.GZ32500@ld-irv-0074> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: linux-pm@vger.kernel.org Cc: "R.Durgadoss" , Len Brown , Lukasz Majewski , Eduardo Valentin On Tue, Mar 31, 2015 at 03:43:48PM -0700, Brian Norris wrote: > Particularly, I'm looking right now at using the uevent/netlink > notification mechanism. It seems that this is only active when we use > the 'user_space' governor, meaning I can't get any user-space > notifications when using the in-kernel governor. Am I missing something, > or is this a known limitation? Is there any reason we can't enable both? > For the user-space side, I'd mostly be interested in being a consumer; > e.g., display warnings in high-temperature scenarios; although I might > also use it to trigger some user-space cooling mechanisms. I'm noticing two additional interesting details. 1. There's a separate netlink event mechanism that has never been used. See generate_netlink_event(), from this commit: commit 4cb18728709683c91a5f6f8d5f337bfb498b089a Author: R.Durgadoss Date: Wed Oct 27 03:33:29 2010 +0530 thermal: Add event notification to thermal framework 2. The Samsung Exynos thermal driver reports uevent info directly, no matter which governor is in use. See exynos_report_trigger(). Is it acceptable to augment drivers in this way, or wouldn't it make more sense to improve the core framework to support this type of notification? Brian