Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752078Ab2KLF4A (ORCPT ); Mon, 12 Nov 2012 00:56:00 -0500 Received: from mga03.intel.com ([143.182.124.21]:7039 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751998Ab2KLFzx convert rfc822-to-8bit (ORCPT ); Mon, 12 Nov 2012 00:55:53 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.80,759,1344236400"; d="scan'208";a="216335799" From: "R, Durgadoss" To: Amit Kachhap , "Zhang, Rui" CC: "linux-pm@lists.linux-foundation.org" , "linux-samsung-soc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "lenb@kernel.org" , "linux-acpi@vger.kernel.org" , "jonghwa3.lee@samsung.com" Subject: RE: [PATCH 1/4] thermal: Add new thermal trend type to support quick cooling Thread-Topic: [PATCH 1/4] thermal: Add new thermal trend type to support quick cooling Thread-Index: AQHNvWlKuI/lwtvFeEqAROZO0ibuK5ffFgeAgAAG54CAAWboAIAAKhGAgAUJ8dA= Date: Mon, 12 Nov 2012 05:55:48 +0000 Message-ID: <4D68720C2E767A4AA6A8796D42C8EB59206068@BGSMSX101.gar.corp.intel.com> References: <1352348786-24255-1-git-send-email-amit.kachhap@linaro.org> <1352348786-24255-2-git-send-email-amit.kachhap@linaro.org> <1352354503.2190.7.camel@rzhang1-mobl4> <1352433060.2166.3.camel@rzhang1-mobl4> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.223.10.10] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3141 Lines: 78 Hi Amit/Rui, > -----Original Message----- > From: Amit Kachhap [mailto:amit.kachhap@linaro.org] > Sent: Friday, November 09, 2012 11:52 AM > To: Zhang, Rui > Cc: linux-pm@lists.linux-foundation.org; linux-samsung- > soc@vger.kernel.org; linux-kernel@vger.kernel.org; R, Durgadoss; > lenb@kernel.org; linux-acpi@vger.kernel.org; jonghwa3.lee@samsung.com > Subject: Re: [PATCH 1/4] thermal: Add new thermal trend type to support > quick cooling > > On 9 November 2012 09:21, Zhang Rui wrote: > > On Thu, 2012-11-08 at 11:56 +0530, Amit Kachhap wrote: > >> On 8 November 2012 11:31, Zhang Rui wrote: > >> > On Thu, 2012-11-08 at 09:56 +0530, Amit Daniel Kachhap wrote: > >> >> This modification adds 2 new thermal trend type > THERMAL_TREND_RAISE_FULL > >> >> and THERMAL_TREND_DROP_FULL. This thermal trend can be used to > quickly > >> >> jump to the upper or lower cooling level instead of incremental > increase > >> >> or decrease. > >> > > >> > IMO, what we need is a new more aggressive cooling governor which > always > >> > uses upper limit when the temperature is raising and lower limit when > >> > the temperature is dropping. > >> Yes I agree that a new aggressive governor is the best approach but > >> then i thought adding a new trend type is a simple solution to achieve > >> this and since most of the governor logic might be same as the > >> step-wise governor. I have no objection in doing it through governor. > >> > > > hmmm, > > I think a more proper way is to set the cooling state to upper limit > > when it overheats and reduce the cooling state step by step when the > > temperature drops. > > No actually I was thinking of having a simple governor with a feature > like it only sets to upper level and lower level. Also since the > temperature sensor is capable of interrupting for both increase in > threshold(say 100C) and fall in threshold (say 90C), so polling or > step increments is not needed at all. > Currently stepwise governor governor does that so we might change the > macro name as, > THERMAL_TREND_RAISE_STEP, > THERMAL_TREND_DROP_STEP, > THERMAL_TREND_RAISE_MAX, > THERMAL_TREND_DROP_MAX, > > and file step_wise.c can be named as state_wise.c or trend_wise.c. Yes, in this particular case, we neither need to poll nor do step wise operations. But, most of the other sensors need at least one of them. So, I think we can try it this way: if (sensor supports interrupt) { 'always' use RAISE_MAX and DROP_MAX; } else { Do Step wise operations } And this could be plugged into step wise. I don't think we need a complete new governor just to get this case working. For this to work, we need a way for the governor to know 'whether the sensor can work on interrupt mode'. May be introducing a new field in tzd structure can help us here. I am fine with any name for the governor :-) Thanks, Durga -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/