Re: [RFC] Pushing device/driver binding decisions to userspace

[Greg KH <greg@kroah.com>]

On Sun, Nov 12, 2006 at 09:22:44PM -0800, Ben Collins wrote:
> On Sun, 2006-11-12 at 17:47 -0800, Nicholas Miell wrote:
> > On Sun, 2006-11-12 at 17:24 -0800, Ben Collins wrote:
> > > On Sun, 2006-11-12 at 16:49 -0800, Nicholas Miell wrote:
> > > > On Sun, 2006-11-12 at 15:39 -0800, Ben Collins wrote:
> > > > 
> > > > What's wrong with making udev or whatever unbind driver A and then bind
> > > > driver B if the driver bound by the kernel ends up being the wrong
> > > > choice? (Besides the inelegance of the kernel choosing one and then
> > > > userspace immediately choosing the other, of course.)
> > > > 
> > > > I'd argue that having multiple drivers for the same hardware is a bit
> > > > strange to begin with, but that's another issue entirely.
> > > 
> > > If two drivers are loaded for the same device, there's no way for udev
> > > to tell the kernel which driver to use for a device, that I know of.
> > 
> > /sys/bus/*/drivers/*/{bind,unbind}
> 
> "bind" does not tell the driver core to "bind this device with this
> driver", it tells it to "bind this driver to whatever devices we match
> that aren't already bound".

No it does not, it tells the driver core to "bind this device with this
driver, _if_ the driver will accept it".

> That doesn't solve my use case.

Yes it does:
	echo -n BUS_ID > /sys/bus/foo_bus/drivers/foo_driver/unbind
	echo -n BUS_ID > /sys/bus/foo_bus/drivers/baz_driver/bind

and you are set.  That's the way other distros use this functionality :)

thanks,

greg k-h