[lm-sensors] [0/6] New w1 features.

[dmitry.torokhov@gmail.com (Dmitry Torokhov)]

On 6/3/05, Evgeniy Polyakov <johnpol@2ka.mipt.ru> wrote:
> On Sat, 4 Jun 2005 01:58:36 +0400
> Evgeniy Polyakov <johnpol@2ka.mipt.ru> wrote:
> 
> > On Fri, 3 Jun 2005 16:46:48 -0500
> > Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote:
> >
> > > On 6/3/05, Evgeniy Polyakov <johnpol@2ka.mipt.ru> wrote:
> > > >
> > > > 6. I wrote reconnect feature: if on start there are no
> > > > registered families all new devices will have defailt family,
> > > > later when driver for appropriate family is loaded, slaves,
> > > > which were faound earlier, will still have defult family instead
> > > > of right one. Reconnect feature will force control thread to
> > > > run through all master devices and all slaves found
> > > > and search for slaves with default family id and try to reconnect
> > > > them.
> > >
> > > Yep, start with one kludge and you'll end up with 10 more.
> > >
> > > Would you mind explaining why a w1 device has to be bound to a family
> > > before it can show in sysfs? We don't have such limitation on other
> > > buses, why is it needed for w1?
> >
> > Because w1 device does not have any sence without appropriate family driver.
> > You may have a device without a driver for it.
> > All buses support it - see dmesg when new device was added but there is
> > no driver for that - usb bus magically says slot is used.
> > Here is the same.
> 
> And, btw, it is _very_ bad that other buses [not usb and not scsi at least]
> do not have such reconnect feature. You can plug your device in, system
> failed to detect it, and later, when you found a driver, you may not access
> it from it's driver.

Oh, really? For some reason when I plug my USB enclosure into the port
it even loads all necessary drivers. So somehow it manages to
recognize device without having a driver for it and then, after
loading proper driver, "reconnects".

Btw, that's what my modalias patch was doing for w1 as well.

> It looks like you do not know how w1 works - there is
> only one possibility to access w1 device - through appropriate bus master,
> so bus muster either has to know about all devices found during the last
> search, which is currently implemented, or perform new search each time
> new device driver is added which is bogus.
> Other buses support some notification about devices plugged to it,
> that is why you do not see some kind of reconnects there, w1 does not,
> so it has to reconnect.

If you don't bind to a driver to begin with you don't have to reconnect, do you?

-- 
Dmitry