RE: Device-dedicated memory (IRP_MN_QUERY_RESOURCE_REQUIR EMENTS)

NTDEV
1

> I’m confused. What device does this 16K buffer belong to?
It is a special industrial keyboard.

What bus is this device attached to?

Well, I have set “legacy, non-enumerable” in the geninf.exe wizard. All my
input comes from the dual-port memory mapped to the memory space.

It is the driver for this device that needs to allocate the resources.

IRP_MN_QUERY_RESOURCE_REQUIREMENTS, as the ddk clearly indicates, is a bus
driver PnP request.

=====================
Mark Roddy
Hollis Technology Solutions
www.hollistech.com
xxxxx@hollistech.com

-----Original Message-----
From: Ferenc Deak [mailto:xxxxx@nct.hu]
Sent: Friday, August 22, 2003 9:22 AM
To: Windows System Software Developers Interest List
Subject: [ntdev] Device-dedicated memory
(IRP_MN_QUERY_RESOURCE_REQUIREMENTS)

Hi,

I would like to access my dual port memory from my keyboard port driver.
The
physical address of the dual port memory is 0x000b0000. It is 16 KByte. I
would like to allocate it for exlusive usage.

I do this in my AddDevice now:

physAddr_dual.LowPart = 0x000b0000;
physAddr_dual.HighPart = 0x00000000;

// map 4 bytes from dual-port memory
devExt->DualRam = MmMapIoSpace(physAddr_dual,4,MmNonCached);

It works, but I have read about

IRP_MN_QUERY_RESOURCE_REQUIREMENTS.(http://msdn.microsoft.com/library/defaul

t.asp?url=/library/en-us/kmarch/hh/kmarch/memmgmt_7o6f.asp)

Now I handle it like this:

case IRP_MN_QUERY_RESOURCE_REQUIREMENTS:

IoSkipCurrentIrpStackLocation(Irp);
status = IoCallDriver(devExt->TopOfStack, Irp);

break;

How can I allocate this 16KByte properly? How should
IRP_MN_QUERY_RESOURCE_REQUIREMENTS be handled? Probably I must modify the
list on the IRP’s way back up the device stack. “If a … driver changes
the
size of the resource requirements list, the driver must allocate a new
structure from paged memory and free the previous structure” (DDK) How?

Is there sample for allocating physical memory?

Thanks in advance,

Ferenc

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

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Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

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