From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755155Ab3KTUPn (ORCPT ); Wed, 20 Nov 2013 15:15:43 -0500 Received: from comal.ext.ti.com ([198.47.26.152]:57180 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754809Ab3KTUPk (ORCPT ); Wed, 20 Nov 2013 15:15:40 -0500 Message-ID: <528D1784.8080704@ti.com> Date: Wed, 20 Nov 2013 22:11:48 +0200 From: Grygorii Strashko User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Stephen Boyd , Len Brown , Pavel Machek , "Rafael J. Wysocki" , Greg Kroah-Hartman CC: , , , , Mike Turquette Subject: Re: [PATCH] PM / Clocks: fix pm_clk_resume/suspend if CONFIG_PM_RUNTIME is set References: <1384954307-27094-1-git-send-email-grygorii.strashko@ti.com> <528D0296.1070001@codeaurora.org> <528D082C.3040405@ti.com> <528D1327.7080205@codeaurora.org> In-Reply-To: <528D1327.7080205@codeaurora.org> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.167.145.75] X-EXCLAIMER-MD-CONFIG: f9c360f5-3d1e-4c3c-8703-f45bf52eff6b Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/20/2013 09:53 PM, Stephen Boyd wrote: > On 11/20/13 11:06, Grygorii Strashko wrote: >> On 11/20/2013 08:42 PM, Stephen Boyd wrote: >>> On 11/20/13 05:31, Grygorii Strashko wrote: >>>> @@ -230,7 +230,7 @@ int pm_clk_suspend(struct device *dev) >>>> list_for_each_entry_reverse(ce, &psd->clock_list, node) { >>>> if (ce->status < PCE_STATUS_ERROR) { >>>> if (ce->status == PCE_STATUS_ENABLED) >>>> - clk_disable(ce->clk); >>>> + clk_disable_unprepare(ce->clk); >>>> ce->status = PCE_STATUS_ACQUIRED; >>>> } >>>> } >>>> @@ -259,7 +259,7 @@ int pm_clk_resume(struct device *dev) >>>> >>>> list_for_each_entry(ce, &psd->clock_list, node) { >>>> if (ce->status < PCE_STATUS_ERROR) { >>>> - clk_enable(ce->clk); >>>> + clk_prepare_enable(ce->clk); >>>> ce->status = PCE_STATUS_ENABLED; >>>> } >>>> } >>> This is inside a spin_lock_irqsave(). You should be getting scheduling >>> while atomic warnings with this change. Are you testing with >>> DEBUG_ATOMIC_SLEEP=y? >> Ops, thanks. No, It's not tested with DEBUG_ATOMIC_SLEEP and >> I agree with you. >> >> So, I see two option here: >> 1) split above loops on two >> 2) add calls of clk_prepare()/clk_unprepare() in pm_clk_notify() >> >> In my opinion option [2] is better. >> > > Doesn't that mean the clock will always be prepared as long as the > device is present? That doesn't sound good. I would like the clocks to > be disabled and unprepared as long as the device is suspended. Yep ( > > What is the lock protecting? The linked list or something more? Can we > remove the locks? Looks like it's protecting linked list pm_clock_entry'es. > > It looks like even if you just remove the locks here, the PM core is > free to call this function with irqs disabled if pm_runtime_irq_safe() > has been called on the device. Perhaps runtime PM can only do the > clk_enable()/clk_disable() part and the clk_unprepare()/clk_prepare() > calls should happen in the system suspend callbacks? Even don't know what to say :( On Keystone clk_unprepare()/clk_prepare() are NOPs. But clk_prepare() has to be called at least once before clk_enable() :(( So, solution with suspend/resume will not fix current problem :( unfortunately. FYI, Now pm_clk_suspend/pm_clk_resume are called from arch/arm/mach-keystone/pm_domain.c (also similar solution is used by Davinci, but issue has not been detected because PM runtime hasn't been used by Davinci IP drivers before) Regards, - grygorii