From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Hilman Subject: Re: [PATCH 2/9] PM / Domains: Remove dev->driver check for runtime PM Date: Thu, 13 Aug 2015 20:40:42 -0700 Message-ID: <7hwpwylepx.fsf@deeprootsystems.com> References: <1438731339-58317-1-git-send-email-lina.iyer@linaro.org> <1438731339-58317-3-git-send-email-lina.iyer@linaro.org> <7hfv3onv5c.fsf@deeprootsystems.com> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from mail-pa0-f49.google.com ([209.85.220.49]:36118 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932081AbbHNDkq (ORCPT ); Thu, 13 Aug 2015 23:40:46 -0400 Received: by pacrr5 with SMTP id rr5so51026571pac.3 for ; Thu, 13 Aug 2015 20:40:45 -0700 (PDT) In-Reply-To: (Geert Uytterhoeven's message of "Thu, 13 Aug 2015 10:57:38 +0200") Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Geert Uytterhoeven Cc: Lina Iyer , "Rafael J. Wysocki" , Ulf Hansson , Krzysztof =?utf-8?Q?Koz=C5=82owski?= , Linux PM list , "linux-arm-kernel@lists.infradead.org" , msivasub@codeaurora.org, Andy Gross , Stephen Boyd Geert Uytterhoeven writes: > Hi Kevin, > > On Wed, Aug 12, 2015 at 9:50 PM, Kevin Hilman wrote: >> Lina Iyer writes: >> >>> Remove check for driver of a device, for runtime PM. Device may be >>> suspended without an explicit driver. This check seems to be vestigial >>> and incorrect in the current context. >> >> This one should probably have been RFC. >> >> For a little more context here, this was uncovered when experimenting >> with using runtime PM for CPU devices which don't have a dev->driver. >> >> This check might have made sense before PM domains, but with PM domains, >> it's entirely possible to have a simple device without a driver and the >> PM domain handles all the necesary PM, so I think this check >> could/should be removed. >> >> Thoughts? > > Simple devices without a driver aren't handled automatically. > At minimum, the driver should call pm_runtime_enable(), cfr. > drivers/bus/simple-pm-bus.c. That's correct, and in the proof-of-concept stuff I hacked up and in Lina's series, the CPU "devices" do indeed to this. Without that, they wouldn't end up ever taking this codepath through genpd's runtime_suspend and power_off hooks. Also, I'm not sure if your comment was meant to be an objection to the patch? or if you're OK with it. Thanks for the feedback, Kevin From mboxrd@z Thu Jan 1 00:00:00 1970 From: khilman@kernel.org (Kevin Hilman) Date: Thu, 13 Aug 2015 20:40:42 -0700 Subject: [PATCH 2/9] PM / Domains: Remove dev->driver check for runtime PM In-Reply-To: (Geert Uytterhoeven's message of "Thu, 13 Aug 2015 10:57:38 +0200") References: <1438731339-58317-1-git-send-email-lina.iyer@linaro.org> <1438731339-58317-3-git-send-email-lina.iyer@linaro.org> <7hfv3onv5c.fsf@deeprootsystems.com> Message-ID: <7hwpwylepx.fsf@deeprootsystems.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Geert Uytterhoeven writes: > Hi Kevin, > > On Wed, Aug 12, 2015 at 9:50 PM, Kevin Hilman wrote: >> Lina Iyer writes: >> >>> Remove check for driver of a device, for runtime PM. Device may be >>> suspended without an explicit driver. This check seems to be vestigial >>> and incorrect in the current context. >> >> This one should probably have been RFC. >> >> For a little more context here, this was uncovered when experimenting >> with using runtime PM for CPU devices which don't have a dev->driver. >> >> This check might have made sense before PM domains, but with PM domains, >> it's entirely possible to have a simple device without a driver and the >> PM domain handles all the necesary PM, so I think this check >> could/should be removed. >> >> Thoughts? > > Simple devices without a driver aren't handled automatically. > At minimum, the driver should call pm_runtime_enable(), cfr. > drivers/bus/simple-pm-bus.c. That's correct, and in the proof-of-concept stuff I hacked up and in Lina's series, the CPU "devices" do indeed to this. Without that, they wouldn't end up ever taking this codepath through genpd's runtime_suspend and power_off hooks. Also, I'm not sure if your comment was meant to be an objection to the patch? or if you're OK with it. Thanks for the feedback, Kevin