From: Dmitry Torokhov <dtor_core@ameritech.net>
To: Greg KH <greg@kroah.com>
Subject: Re: [RFC] [PATCH] driver core: allow userspace to unbind drivers from devices.
Date: Wed, 17 Nov 2004 02:07:14 -0500
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Cc: ambx1@neo.rr.com, linux-kernel@vger.kernel.org, Tejun Heo <tj@home-tj.org>,
       Patrick Mochel <mochel@digitalimplant.org>
References: <20041109223729.GB7416@kroah.com> <20041116061315.GG29574@neo.rr.com> <20041116201726.GA11069@kroah.com>
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On Tuesday 16 November 2004 03:17 pm, Greg KH wrote:
> > 2.) I don't like having an "unbind" file.
> 
> Why?

I do not like interfaces accepting and encouraging writing garbage data. What
value sould be written into "unbind"? Yes, any junk.
 
> 
> > This implies that we will have at least three seperate files controlling
> > driver binding when we really need only one or two at the most. ?Consider
> > "bind", "unbind", and the link to the driver that is bound.
> 
> No. ?Consider the fact that the "unbind" file will not be present if the
> device is not bound to anything. ?Once it is bound, the unbind file will
> be created, and the symlink will be created. ?The symlink matches other
> parts of sysfs. ?By trying to put the name of the driver in a file, that
> makes userspace work a lot harder to try to figure out exactly what
> driver is bound (consider the fact that I can have both a pci and a usb
> driver with the same name in sysfs, and that's legal.)

But not 2 drivers with the same name on the same bus so I don't think this
is a valid argument. Anyway, we already have this symlink.

> 
> So, when a device is not bound to a driver, there will be no symlink, or
> a "unbind" file, only a "bind" file. ?Really there is only 1 "control"
> type file present at any single point in time.

Does that imply that I can not rebind device while it is bound to a driver?
("bind" would be missing it seems). And what about all other flavors of that
operation - rescan, reconnect? Do we want to have separate attributes for
them as well?

-- 
Dmitry
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