From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [PATCH 02/11] PM: extend PM QoS with per-device wake-up constraints Date: Sun, 21 Aug 2011 20:05:53 +0200 Message-ID: <201108212005.53898.rjw__30692.4885874198$1313949905$gmane$org@sisk.pl> References: <20110820062543.GA5011@opensource.wolfsonmicro.com> <201108202114.37502.rjw@sisk.pl> <20110821082509.GA10380@opensource.wolfsonmicro.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20110821082509.GA10380@opensource.wolfsonmicro.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Mark Brown Cc: Linux PM mailing list , linux-omap@vger.kernel.org, Jean Pihet , markgross@thegnar.org List-Id: linux-pm@vger.kernel.org On Sunday, August 21, 2011, Mark Brown wrote: > On Sat, Aug 20, 2011 at 09:14:37PM +0200, Rafael J. Wysocki wrote: > > > I guess you mean the driver here and I'm not really sure it can. > > For instance, the driver may not know what configuration it works in, > > e.g. is there a power domain or a hierarchy of those and how much time > > it takes to power them all down and up and what the power break even is. > > I don't understand why the driver would need to know what situation it's > in. I'd been working on the basis that the idea was that the driver > said what the constraints it has are and then some code with a more > system wide view would make the actual decisions for things outside the > driver domian. That's correct, but in order to figure out a "sensible default" the driver generally would need to know what the expectations with respect to it are. Otherwise it can very well generate a random number and use that. Thanks, Rafael