Writing Virtual Device Driver

Hello
I like to know how do virtual drivers work and how they are made, please
kindly provide me with suggestions and links

regards
Mahesh

Tim
Thu Nov 24 23:39:35 CST 2005

"Mahesh" <maheshstms@gmail.com> wrote:
>
>I like to know how do virtual drivers work and how they are made, please
>kindly provide me with suggestions and links

That term is overloaded. What are you actually trying to accomplish?
--
- Tim Roberts, timr@probo.com
Providenza & Boekelheide, Inc.

Mahesh
Sat Nov 26 09:20:09 CST 2005

I like to watch communication between Host and USB controller, so i have a
idea of creating a virtual USB controller driver.
The driver will watch data to the virtul device and will print it to a file
or will send it to my application.

thanks
Mahesh

"Tim Roberts" <timr@probo.com> wrote in message
news:vr8do1pknjaj10e9aqg2nmeajm5ok363p5@4ax.com...
> "Mahesh" <maheshstms@gmail.com> wrote:
> >
> >I like to know how do virtual drivers work and how they are made, please
> >kindly provide me with suggestions and links
>
> That term is overloaded. What are you actually trying to accomplish?
> --
> - Tim Roberts, timr@probo.com
> Providenza & Boekelheide, Inc.

Tim
Tue Nov 29 00:09:11 CST 2005

"Mahesh" <maheshstms@gmail.com> wrote:
>
>I like to watch communication between Host and USB controller, so i have a
>idea of creating a virtual USB controller driver.

Well, a virtual USB controller driver isn't going to show you that
communication. In fact, to be a virtual controller driver, you have to
PROVIDE that communication.

>The driver will watch data to the virtul device and will print it to a file
>or will send it to my application.

I'm still not clear on what you hope to learn. There are several products
to monitor traffic on a USB bus, both inside and outside of the computer.
Drivers communicate with the host controller driver via URBs, and there are
many examples of those in the DDK.

If you want to learn how to program a host controller, that is a difficult
task. You can download the OHCI spec, which tells you the general theory
of operation of one type of host controller.

If you want more details, I recommend you go download Linux. There, you
get the source for everything, to look through at your leisure.
--
- Tim Roberts, timr@probo.com
Providenza & Boekelheide, Inc.

Mahesh
Thu Dec 01 13:11:32 CST 2005

> Well, a virtual USB controller driver isn't going to show you that
> communication. In fact, to be a virtual controller driver, you have to
> PROVIDE that communication.

I am currently in the field of making application's for USB Devices. I just
wanted myself to be strong enough in the device detection part by the OS
I thought of making a Virtual USB controller driver, which will receive all
packets sent by OS. I will log them and view them using SoftIce

My driver will handle all calls by the OS, it will respond as if a Keyboard
is connected or any other device of my choice

Is my concept wrong.

Suggest me a idea

regards
Mahesh

"Tim Roberts" <timr@probo.com> wrote in message
news:5brno19cdvki29btolle31ghi78qnmib4h@4ax.com...
> "Mahesh" <maheshstms@gmail.com> wrote:
> >
> >I like to watch communication between Host and USB controller, so i have
a
> >idea of creating a virtual USB controller driver.
>
> Well, a virtual USB controller driver isn't going to show you that
> communication. In fact, to be a virtual controller driver, you have to
> PROVIDE that communication.
>
> >The driver will watch data to the virtul device and will print it to a
file
> >or will send it to my application.
>
> I'm still not clear on what you hope to learn. There are several products
> to monitor traffic on a USB bus, both inside and outside of the computer.
> Drivers communicate with the host controller driver via URBs, and there
are
> many examples of those in the DDK.
>
> If you want to learn how to program a host controller, that is a difficult
> task. You can download the OHCI spec, which tells you the general theory
> of operation of one type of host controller.
>
> If you want more details, I recommend you go download Linux. There, you
> get the source for everything, to look through at your leisure.
> --
> - Tim Roberts, timr@probo.com
> Providenza & Boekelheide, Inc.

Tim
Sat Dec 03 12:51:13 CST 2005

"Mahesh" <maheshstms@gmail.com> wrote:
>
>I am currently in the field of making application's for USB Devices. I just
>wanted myself to be strong enough in the device detection part by the OS
>I thought of making a Virtual USB controller driver, which will receive all
>packets sent by OS. I will log them and view them using SoftIce
>
>My driver will handle all calls by the OS, it will respond as if a Keyboard
>is connected or any other device of my choice
>
>Is my concept wrong.

Your concept is wrong. The "operating system" doesn't send and receive USB
packets. That is done *BY* the host controller driver.

The host controller driver has to manage device discovery, and report the
new devices to the I/O subsystem. USB device drivers send URBs (USB
request blocks) to the HCD when they want to read or write data. URBs are
high-level structures. The HCD then chops these up into packets and
schedules them for delivery on the bus itself.

Do you see the problem? In order to write a virtual HCD, you need to be
intimately familiar with all of the operations you hope to learn about.

Device detection in USB is very simple. If there is something about it
that concerns you, you should ask that specific question. The path you are
travelling will not lead to enlightenment.
--
- Tim Roberts, timr@probo.com
Providenza & Boekelheide, Inc.