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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Daniel Kurtz <djkurtz@chromium.org>, Ulf Hansson <ulf.hansson@linaro.org>,
        Russell King <linux@arm.linux.org.uk>,
        "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
        Tony Lindgren <tony@atomide.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Kevin Hilman <khilman@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        Alan Stern <stern@rowland.harvard.edu>, Pavel Machek <pavel@ucw.cz>,
        Tomas Winkler <tomas.winkler@intel.com>,
        "linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
        Len Brown <lenb@kernel.org>
Subject: Re: [PATCH v11 2/4] PM / Domains: add setter for dev.pm_domain
Date: Fri, 08 Jan 2016 01:20:08 +0100
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On Thursday, January 07, 2016 03:47:01 PM Tomeu Vizoso wrote:
> On 10 November 2015 at 10:33, Daniel Kurtz <djkurtz@chromium.org> wrote:
> [snip]
> >
> > The problem appears to be that:
> >   * On boot, platform_drv_probe() calls dev_pm_domain_attach() before
> > drv->probe(); thus, it calls dev_pm_domain_attach() while the device
> > is unbound.
> >
> >  * However, for a platform_device, the reboot path calls
> > device_shutdown(), but not __device_release_driver():
> > device_shutdown()
> >   dev->driver->shutdown => platform_drv_shutdown()
> >     dev_pm_domain_detach()
> >        dev->pm_domain->detach() => genpd_dev_pm_detach()
> >          pm_genpd_remove_device()
> >             dev_pm_domain_set(dev, NULL);
> >
> > So, for a platform_device in a genpd power domain with .shutdown
> > installed, platform_drv_shutdown() calls dev_pm_domain_detach() while
> > the device is still bound, which triggers the WARN().
> 
> Hi Rafael, Alan and Ulf,
> 
> do you have any suggestion about this? I don't really understand why
> the device is detached from the domain on shutdown.

Well, this looks like a bug to me.

Thanks,
Rafael