Node creation For real time devices

[manty kuma]

Hi Philipp,

The flow you mentioned is something which I was not aware of. I would like
to see it happening in code.

My Queries are as follows:

1) " The kernel then creates an uevent and notifies the userspace part of
udev (udevd) through a netlink socket. " -  What are the corresponding
files that i need to check? If the question is too abstract, kindly explain
me with respect to any sample Bus.

2)  "The uevent is received by udevd and now udev can check for rules to
add the device node to /dev" - Again the same thing. I would like to see it
inside the code. Please help me in looking at the real code.

Thanks again Philipp for your valuable answer.

Regards,
-Manty
On Fri, Apr 20, 2012 at 7:24 PM, Philipp Ittershagen <
p.ittershagen at googlemail.com> wrote:

> Hi Manty!
>
> On Fri, Apr 20, 2012 at 3:29 PM, manty kuma <mantykuma at gmail.com> wrote:
> > Hi,
> >
> > I want to know how a node is created when a hardware is connected to the
> > system.
> >
> > Information that I know :
> > When a hardware is connected to the system, the device name is compared
> with
> > the driver name, if it matches, then probe is called.
> >
> > Info i wish to know:
> > At which point is the node created and who is creating it(In other
> words, i
> > want to know where is mknod happening)?
> >
> > This one thing is bugging my mind from so many months. Please tell me
> > programatically where is this happening. I will be very thankful.
>
> Please correct me if I'm wrong, my understanding is this:
>
> The hardware is connected and the corresponding subsystem or bus will
> be notified (i.e. by interrupt of the device). The kernel then creates
> an uevent and notifies the userspace part of udev (udevd) through a
> netlink socket. The uevent is received by udevd and now udev can check
> for rules to add the device node to /dev. That's when the creation and
> naming of the device node happens.
>
>
> Greetings,
>
>  Philipp
>
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