From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH 01/04] OMAP3: PM: Disable PER DPLL idle before OFF, reduces OFF latency by 20ms Date: Tue, 30 Jun 2009 15:24:28 -0700 Message-ID: <87bpo55pib.fsf@deeprootsystems.com> References: <5A47E75E594F054BAF48C5E4FC4B92AB0305B77F0D@dbde02.ent.ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from wf-out-1314.google.com ([209.85.200.174]:23888 "EHLO wf-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753254AbZF3WY2 (ORCPT ); Tue, 30 Jun 2009 18:24:28 -0400 Received: by wf-out-1314.google.com with SMTP id 26so171604wfd.4 for ; Tue, 30 Jun 2009 15:24:31 -0700 (PDT) In-Reply-To: <5A47E75E594F054BAF48C5E4FC4B92AB0305B77F0D@dbde02.ent.ti.com> (Rajendra Nayak's message of "Tue\, 30 Jun 2009 11\:28\:18 +0530") Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: "Nayak, Rajendra" Cc: Kalle Jokiniemi , "linux-omap@vger.kernel.org" , "Derrick, David" , "Woodruff, Richard" "Nayak, Rajendra" writes: [...] >>> >>> Oh.. it turns out that when the scratchpad save routine is called, >>> the autoidle for PER is not even set. Its only set some place >>> later. So the 20ms or so advantage was always there on l-o pm >>> branch even without this patch :) >>> >> >>So for the benefit of the archives... >> >>I'm dropping this patch since the equivalent is alrady in PM branch. > > Today the sequence is such that the PER dpll autoidle is set only > after the first scratchpad save (so this patch has no > affect). Sometime in future, if with some change in function > sequencing we end up enabling the PER dpll autoidle early on, we > might have an additional 20ms or so OFF latency without anyone > really noticing. Would'nt it be good to just have this patch to > take care of any sequencing changes later? Yes, I think you're right. This change could indeed prevent some future problmes down the road. I'll merge it. Thanks, Kevin