linuxconsole-dev

A modest proposal...

[Charles D. <cd...@mv...>]

Howdy.

I notice that, at present, several of the handlers (such as evdev)
assign device numbers independantly. Hence, /dev/input/event2 and
/dev/input/mouse2 may not refer to the same device, and (similarly)
may not refer to the device dubbed input2 on initialization.

Might it not make for a somewhat more user-friendly world to have
handlers use dev->number for determining the minor number for each
connected device?

This would also make a table of connected input devices somewhat more
useful.

Re: A modest proposal...

[Vojtech P. <vo...@su...>]

On Sun, Jun 24, 2001 at 12:41:45AM -0700, Charles Duffy wrote:
> Howdy.
> 
> I notice that, at present, several of the handlers (such as evdev)
> assign device numbers independantly. Hence, /dev/input/event2 and
> /dev/input/mouse2 may not refer to the same device, and (similarly)
> may not refer to the device dubbed input2 on initialization.
> 
> Might it not make for a somewhat more user-friendly world to have
> handlers use dev->number for determining the minor number for each
> connected device?
> 
> This would also make a table of connected input devices somewhat more
> useful.

Sounds reasonable to start searching for free numbers at the dev->number
position. What others think?

-- 
Vojtech Pavlik
SuSE Labs

Re: A modest proposal...

[James S. <jsi...@tr...>]

> > Howdy.
> > 
> > I notice that, at present, several of the handlers (such as evdev)
> > assign device numbers independantly. Hence, /dev/input/event2 and
> > /dev/input/mouse2 may not refer to the same device, and (similarly)
> > may not refer to the device dubbed input2 on initialization.
> > 
> > Might it not make for a somewhat more user-friendly world to have
> > handlers use dev->number for determining the minor number for each
> > connected device?
> > 
> > This would also make a table of connected input devices somewhat more
> > useful.
> 
> Sounds reasonable to start searching for free numbers at the dev->number
> position. What others think?

   Is it possible to match them up like that? I was thinking about it and
to me it seems like a huge task. Unless I miss understood what he
suggested.
   One thing I like to bring up about numbering is when you plug and
unplug devices. At present when you unplug a device and plug it back in
the device becomes /dev/input/event[n+1]. Where /dev/input/event[n] now
has no device attached. There is a limit to 256 event devices. Now you
say that is a good number but given 5 input devices it whould take 15
times unplugging and plugging them back in before you run out of numbers.
So I like to suggest that we keep track of the "free" numbers and grab the
lowest one. Say you have 5 devices and you unplug device 3 and then plug
it back it then it should be device 3 again. Not device 6. 

P.S

   My iPAQ input touchscreen driver went into the handhelds tree.
HaHooooo! Once compaq transfers over I hope to see others transfer over.

Re: A modest proposal...

[Vojtech P. <vo...@su...>]

On Wed, Jun 27, 2001 at 09:52:46AM -0700, James Simmons wrote:
> 
> > > Howdy.
> > > 
> > > I notice that, at present, several of the handlers (such as evdev)
> > > assign device numbers independantly. Hence, /dev/input/event2 and
> > > /dev/input/mouse2 may not refer to the same device, and (similarly)
> > > may not refer to the device dubbed input2 on initialization.
> > > 
> > > Might it not make for a somewhat more user-friendly world to have
> > > handlers use dev->number for determining the minor number for each
> > > connected device?
> > > 
> > > This would also make a table of connected input devices somewhat more
> > > useful.
> > 
> > Sounds reasonable to start searching for free numbers at the dev->number
> > position. What others think?
> 
>    Is it possible to match them up like that? I was thinking about it and
> to me it seems like a huge task. Unless I miss understood what he
> suggested.

We can't match them completely, but we should be able to make a good
approximation if the user doesn't do too nasty things to the system.

>    One thing I like to bring up about numbering is when you plug and
> unplug devices. At present when you unplug a device and plug it back in
> the device becomes /dev/input/event[n+1]. Where /dev/input/event[n] now
> has no device attached.

Only if it is open. If it is not, it'll become /dev/input/event[n]

> There is a limit to 256 event devices. Now you
> say that is a good number but given 5 input devices it whould take 15
> times unplugging and plugging them back in before you run out of numbers.
> So I like to suggest that we keep track of the "free" numbers and grab the
> lowest one.

We do this, at least in evdev.

> Say you have 5 devices and you unplug device 3 and then plug
> it back it then it should be device 3 again. Not device 6. 

-- 
Vojtech Pavlik
SuSE Labs

Re: A modest proposal...

[James S. <jsi...@tr...>]

> > There is a limit to 256 event devices. Now you
> > say that is a good number but given 5 input devices it whould take 15
> > times unplugging and plugging them back in before you run out of numbers.
> > So I like to suggest that we keep track of the "free" numbers and grab the
> > lowest one.
> 
> We do this, at least in evdev.

Yes but input.c you just increase it from what I could see.

Re: A modest proposal...

[Vojtech P. <vo...@su...>]

On Fri, Jun 29, 2001 at 12:27:10PM -0700, James Simmons wrote:
> 
> > > There is a limit to 256 event devices. Now you
> > > say that is a good number but given 5 input devices it whould take 15
> > > times unplugging and plugging them back in before you run out of numbers.
> > > So I like to suggest that we keep track of the "free" numbers and grab the
> > > lowest one.
> > 
> > We do this, at least in evdev.
> 
> Yes but input.c you just increase it from what I could see.

No:

	dev->number = find_first_zero_bit(input_devices, INPUT_DEVICES);

-- 
Vojtech Pavlik
SuSE Labs

Re: A modest proposal...

[James S. <jsi...@tr...>]

> > Yes but input.c you just increase it from what I could see.
> 
> No:
> 
> 	dev->number = find_first_zero_bit(input_devices, INPUT_DEVICES);

Sorry I was looking at the dev->number = input_number which is always
increased and decreased.