Re: [ACPI] Re: 2.6.10-rc1-mm3: ACPI problem due to un-exported hotplug_path

Dmitry Torokhov
2004-11-10T04:16:10Z

On Tuesday 09 November 2004 07:08 pm, Greg KH wrote:
> On Tue, Nov 09, 2004 at 06:48:17PM -0500, Dmitry Torokhov wrote:
> > On Tue, 9 Nov 2004 14:55:02 -0800, Greg KH <greg@kroah.com> wrote:
> > > On Fri, Nov 05, 2004 at 09:18:48PM -0800, Keshavamurthy Anil S wrote:
> > > > Also, since you have brought this, I have one another question to you.
> > > > Now in the new kernel, I see whenever anybody calls sysdev_register(kobj),
> > > > an "ADD" notification is sent. why is this? I would like to call
> > > > kobject_hotplug(kobj, ADD) later.
> > >
> > > This happens when kobject_add() is called. You shouldn't ever need to
> > > call kobject_hotplug() for an add event yourself.
> > >
> >
> > This is not always the case. One might want to postpone ADD event
> > until all summpelental object attributes are created. This way userspace
> > is presented with object in consistent state.
>
> No, that's a mess. Let userspace wait for those attributes to show up
> if they need to. That's what the "wait_for_sysfs" program bundled with
> udev is for.
>

I strongly disagree:

- it makes userspace being aware of implementation details (whe exactly it
has to wait for, for how long, etc.) which is bad thing;
- not all the world is udev - needless replication of the code and bugs;
- not only making visible but announcing an object in non-working state
to userspace simply does not feel right.

--
Dmitry