Hardware Resources

NTDEV
1

Hi!,

I have a couple of questions:

The device for which I’m writting a wdm driver has I/O
ports, memory ranges, DMA and IRQs. So I’ve been writing
a basic driver (just to read a port).

  1. My first doubt is: If I only write in my start device
    routine that I have I/O port resources, could be a
    problem? I mean by just ignoring the other resorces, could
    a problem arise?

  2. When the PnP manager sends me a filter resource
    requirements irp, does that mean that there is no
    information about the resources “inside” my device? Or is
    because of my driver??

Thanx
.

2

> 2. When the PnP manager sends me a filter resource

requirements irp, does that mean that there is no

This is a very special IRP. For most cases, just ignore it and send it down.

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com

3

> 1. My first doubt is: If I only write in my start device

routine that I have I/O port resources, could be a
problem? I mean by just ignoring the other resorces, could
a problem arise?



First, the system is going to pass you all of the resources for the device
via resource lists in Start whether you like it or not. What you do with
these resources is up to you. Ignoring all but the ports is fine provided
that you ensure your device does not generate an interrupt of any kind.
Generating an interrupt without hooking up an ISR to service that interrupt
is a sure death sentence to the system. However, it is completely valid to
ignore a memory region or whatever if you so choose.

> 2. When the PnP manager sends me a filter resource
> requirements irp, does that mean that there is no
> information about the resources “inside” my device? Or is
> because of my driver??

If you read the DDK help documentation on this IRP it says:

“The PnP Manager sends this IRP to a device stack so the function driver can
adjust the resources required by the device, if appropriate.”

You will not need to muck with the resource lists using this IRP in most
cases. The Pnp manager is just giving you an opportunity to do so if
necessary.

–
Bill McKenzie
Compuware Corporation
Watch your IRPs/IRBs/URBs/SRBs/NDIS pkts with our free WDMSniffer tool:
http://frontline.compuware.com/nashua/patches/utility.htm

“Rodrigo Zimbron” wrote in message
news:xxxxx@ntdev…
>
> Hi!,
>
> I have a couple of questions:
>
> The device for which I’m writting a wdm driver has I/O
> ports, memory ranges, DMA and IRQs. So I’ve been writing
> a basic driver (just to read a port).
>
> 1. My first doubt is: If I only write in my start device
> routine that I have I/O port resources, could be a
> problem? I mean by just ignoring the other resorces, could
> a problem arise?
>
> 2. When the PnP manager sends me a filter resource
> requirements irp, does that mean that there is no
> information about the resources “inside” my device? Or is
> because of my driver??
>
> Thanx
> .
>
>
>