From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752427AbbCKWOj (ORCPT ); Wed, 11 Mar 2015 18:14:39 -0400 Received: from mail-ie0-f179.google.com ([209.85.223.179]:35797 "EHLO mail-ie0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751525AbbCKWOg (ORCPT ); Wed, 11 Mar 2015 18:14:36 -0400 MIME-Version: 1.0 In-Reply-To: <6516096.HanqZ05BXy@vostro.rjw.lan> References: <1426087648-3862-1-git-send-email-eric@anholt.net> <6516096.HanqZ05BXy@vostro.rjw.lan> Date: Wed, 11 Mar 2015 23:14:05 +0100 X-Google-Sender-Auth: CTAe7cbdxlAZ-cYHyyMrh6vNErg Message-ID: Subject: Re: [PATCH] PM / Domains: If an OF node is found but no device probed yet, defer. From: Geert Uytterhoeven To: "Rafael J. Wysocki" Cc: Eric Anholt , Kevin Hilman , Ulf Hansson , "linux-kernel@vger.kernel.org" , Tomasz Figa , Greg Kroah-Hartman , Linux PM list Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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(). >> 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. Whether this is a good or a bad thing depends on your bootloader. If all PM domains are powered when Linux boots, it can work without PM domain driver. Since DT PM domains are quite recent, I guess this is the case for most existing SoCs. >> struct of_genpd_provider *provider; >> >> mutex_lock(&of_genpd_mutex); Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds