From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932222AbbCMSB2 (ORCPT ); Fri, 13 Mar 2015 14:01:28 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:36006 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752524AbbCMSBY (ORCPT ); Fri, 13 Mar 2015 14:01:24 -0400 From: Kevin Hilman To: Geert Uytterhoeven Cc: "Rafael J. Wysocki" , Eric Anholt , Ulf Hansson , "linux-kernel\@vger.kernel.org" , Tomasz Figa , Greg Kroah-Hartman , Linux PM list Subject: Re: [PATCH] PM / Domains: If an OF node is found but no device probed yet, defer. References: <1426087648-3862-1-git-send-email-eric@anholt.net> <6516096.HanqZ05BXy@vostro.rjw.lan> Date: Fri, 13 Mar 2015 11:01:20 -0700 In-Reply-To: (Geert Uytterhoeven's message of "Wed, 11 Mar 2015 23:14:05 +0100") Message-ID: <7hr3sspyj3.fsf@deeprootsystems.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Geert Uytterhoeven writes: > On Wed, Mar 11, 2015 at 11:08 PM, Rafael J. Wysocki wrote: >> More CCes. >> >> On Wednesday, March 11, 2015 08:27:28 AM Eric Anholt wrote: >>> If we've declared a power domain in the OF, and the OF node is found >>> but the requested domain hasn't been registered on it yet, then we >>> probably have just tried to probe before the power domain driver has. >>> Defer our device's probe until it shows up. >>> >>> Signed-off-by: Eric Anholt >> >> Kevin, Ulf, any chance to have a look at this, please? >> >>> --- >>> >>> I ran into this when turning my ad-hoc code for BCM2835 (Raspberry Pi) >>> USB poweron support in the DWC2 controller to an OF-based power domain >>> declaration. > > I guess you are initializing the PM domains from module_init()? > > I use core_initcall() in arch/arm/mach-shmobile/pm-rmobile.c to make sure it's > initialized earlier, as e.g. the interrupt controller uses postcore_initcall(). Yeah, I think most existing users are initizling PM domains early, but IMO we should be working towards supporting PM domains that are created later as well (as this patch does.) >>> drivers/base/power/domain.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c >>> index ba4abbe..2b93c98 100644 >>> --- a/drivers/base/power/domain.c >>> +++ b/drivers/base/power/domain.c >>> @@ -2064,7 +2064,7 @@ EXPORT_SYMBOL_GPL(of_genpd_del_provider); >>> struct generic_pm_domain *of_genpd_get_from_provider( >>> struct of_phandle_args *genpdspec) >>> { >>> - struct generic_pm_domain *genpd = ERR_PTR(-ENOENT); >>> + struct generic_pm_domain *genpd = ERR_PTR(-EPROBE_DEFER); > > Currently platform_drv_probe() just continues if dev_pm_domain_attach() returns > a different error than -EPROBE_DEFER, which is what you are seeing. > > Your change does have the side effect that a new DT with PM domains won't > work on an older kernel that doesn't have the PM domain driver yet. Is that a real problem though? Using newer DTs on older kernels can cause many types of problems. Kevin