Re: Role of close() in struct input_dev

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

On Tue, Jun 19, 2001 at 10:42:27PM +0200, Johann Deneux wrote:
> On Tue, 19 Jun 2001, James Simmons wrote:
> 
> > 
> > > Now the question is: What is the role of input_dev::close/open ?
> > > Are they meant as "init/deinit the device" or "establish/break connection
> > > with processes" (or a mix of both) ?
> > 
> > If you look at input.c connect and disconnect are used by input_register
> > and input_unregister which are called when you insmod the device or at
> > boot time. So they are used to setup the hardware and the data structs for
> > the device. Now open and close are called input_open_device and
> > input_close_device. Now if look at what calls input_[opne/close]_device
> > they are all some kind of userland interface i.e evdev, mousedev, joydev.c
> > etc. 
> 
> There are parts of evdev functions called by userland, and other parts
> called by other modules. Namely, evdev_disconnect can be called by serio,
> for example.

No, evdev_disconnect will always be called by input.c, which will always
be called by some input device driver calling the unregister() function.

It can be triggered by serio/usb/rmmod/whatever else, though.

> The problem is still there: I would expect
> input_open_device/input_close_devise to be called at least the same
> number of times (perhaps we should even take care of the order).

We can't take care of the order - that is not possible. But they indeed
should be called the same number of times. If they are not, it's a bug.

-- 
Vojtech Pavlik
SuSE Labs