From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Mark A. Greer" Subject: Re: [PATCH 03/12] arm: omap3: Only sleep in cpuidle driver if I/O wake-ups work Date: Mon, 30 Apr 2012 14:34:33 -0700 Message-ID: <20120430213433.GA19256@animalcreek.com> References: <1334171147-7517-1-git-send-email-mgreer@animalcreek.com> <1334171147-7517-4-git-send-email-mgreer@animalcreek.com> <20120424205105.GA26749@animalcreek.com> <20120424232506.GA8850@animalcreek.com> <87haw4282b.fsf@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail20.dotsterhost.com ([66.11.232.73]:46553 "EHLO mail20.dotsterhost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756383Ab2D3Vef (ORCPT ); Mon, 30 Apr 2012 17:34:35 -0400 Content-Disposition: inline In-Reply-To: <87haw4282b.fsf@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: Kevin Hilman Cc: Paul Walmsley , linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org On Fri, Apr 27, 2012 at 02:12:12PM -0700, Kevin Hilman wrote: > "Mark A. Greer" writes: > > > On Tue, Apr 24, 2012 at 01:51:05PM -0700, Mark A. Greer wrote: > > Just thinking out loud... > > > > We could chose whether pm_idle & cpuidle issue a wfi based on > > whether there is a davinci-emac present. The issue with that is > > that someday there may be another SoC that has a davinci-emac that > > can wake up the system. I know cpu_is_xxx() is frowned upon but > > this does seem like a proper usage of it--the deciding factor > > really is whether its an am35x or not (and CONFIG_TI_DAVINCI_EMAC > > is enabled). > > The presence of the davinci_emac is probably overkill, avoiding WFI > should really only be done when the davinci_emac is *active*. > e.g. using an am35x with an EMAC *present*, but not in use because > there's an MMC rootfs for example. > > If there's a good way to detect an in-use davinci_emac, then > disable_hlt() can be used to avoid WFI. When the davinci_emac is not in > use (e.g. module unloaded etc.) then enable_hlt() can be used to > (re)allow WFI. This can work for pm_idle but what should be done for cpu_idle (as in, omap3_enter_idle[_bm])? We should have some sort of solution for that so users can safely enable CONFIG_CPU_IDLE and not have the am3517 fall apart. Mark