Re: [PATCH 4/4] ACPI / PM: Expose lists of device power resources to user space

From: Rafael J. Wysocki
Date: Tue Jan 22 2013 - 19:22:27 EST


On Wednesday, January 23, 2013 01:17:47 AM Rafael J. Wysocki wrote:
> On Wednesday, January 23, 2013 01:08:54 AM Rafael J. Wysocki wrote:
> > On Tuesday, January 22, 2013 03:56:24 PM Greg Kroah-Hartman wrote:
> > > On Tue, Jan 22, 2013 at 03:28:23AM +0100, Rafael J. Wysocki wrote:
>
> [...]
>
> > > Oh, and same question about racing userspace, you will have problems
> > > here in that the symlinks will be showing up after the device is
> > > created. Perhaps, to make the whole thing easier, you just change the
> > > acpi core code to hold off on the notification until you get all of
> > > these links and files set up and then tell userspace. That's probably
> > > an easier fix.
> >
> > I suppose so.
> >
> > How can I do that?
>
> Should I set dev->kobj.uevent_suppress before calling device_register() and
> then clear it and call the kobject_uevent(&dev->kobj, KOBJ_ADD) from the ACPI
> core after device_register() has returned and the files have been created?

I suppose along the lines of how firmware_class.c uses uevent_suppress?

Is there any safe mechanism for adding/removing sysfs attributes after
kobject_uevent(&dev->kobj, KOBJ_ADD) has been called for the given device?

Rafael


--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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