Date: Mon, 07 Jan 2002 12:36:32 -0800
From: David Brownell <david-b@pacbell.net>
Subject: Re: Hardware Inventory [was: Re: ISA slot detection on PCI systems?]
To: Greg KH <greg@kroah.com>, lkml <linux-kernel@vger.kernel.org>,
        mochel@osdl.org
Message-id: <17b801c197ba$febd13c0$6800000a@brownell.org>
MIME-version: 1.0
Content-type: text/plain; charset=iso-8859-1
Content-transfer-encoding: 7BIT
Sender: linux-kernel-owner@vger.kernel.org

> > /sbin/hotplug is called from the kernel only, right?
>
> Right.  But there's no reason it can't be called from any other place.
> It's just a userspace program with a well documented interface :)

Actually, it's already called from other places ... :)
/sbin/hotplug is called from the init.d/hotplug startup script.

There's a period during initial system boot when not all filesystems
or system services are available.  When the kernel calls out to
/sbin/hotplug in such a situation, hotplugging can't yet do it's job.

It's too early, the system isn't "hot" yet ... which is why I call this
problem the "coldplug" issue.   Even simple device setup
operations like modprobing may not be possible, much less
more complex ones like alerting/starting daemons.  So the
init.d/hotplug script, invoked later, fakes hotplug events to
make sure the same setup gets done, without requiring users
to unplug/replug devices.

- Dave


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/