Re: [RFC] [PATCH] driver core: allow userspace to unbind drivers from devices.

Dmitry Torokhov
2004-11-17T19:05:46Z

On Wed, 17 Nov 2004 09:53:59 -0800, Greg KH <greg@kroah.com> wrote:
> On Wed, Nov 17, 2004 at 02:07:14AM -0500, Dmitry Torokhov wrote:
> > 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.
>
> Ok, we restrict it to working only if you write a "1" into it. That was
> an easy fix :)
>
> > > 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?
>
> Yes. You must unbind it first.
>
> > ("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?
>
> rescan is a bus specific thing, not a driver or device thing.

Yes, it is - at least when I am talking about rescan I mean that I want to
scan a bus for a specific driver for the particular device. I do not want any
other device to be affected and therefore it is a device thing.

> reconnect would be the same as "unbind" + "bind" and you can do that
> with the scheme I posted.

No quite - the point of reconnect is to be able to re-intialize the hardware
while keeping everything else intact - if I do unbind and then bind on my
touchpad while GPM and X are running it will jump from /dev/input/event0
to /dev/input/event4 and I will effectively lose it.

--
Dmitry