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From: Peter on 2 Apr 2008 11:40
Hi!

Is it possible for a miniport driver to allocate more than one DMA handles?
We are working with a device that supports a multi-function device and would
like to separate DMA access bewteen these functions by using separate DMA
handles. While this appears to work with free-build NDIS, I see the checked
NDIS trigger the assert I show above.

Naturally, the WDK is unclear about the limitations the driver faces with
calls to NdisMRegisterScatterGatherDma, so any help to clarify this would be
helpful.

Thanks!


From: Alireza Dabagh [MS] on 14 Apr 2008 03:24
Unfortunately even though free NDIS succeeds the call, it just overwrites
the old handle with the new one. I think bad things can happen in this case.
We should fix the call to return failure.

So the answer to your question is no, a miniport adapter can get only one
DMA handle. and I am not sure what you really gain by giving a separate
handle to each function if those functions are not exposed to OS.

If these functions are real PCI functions, we should have two miniport
adapters in the first place. In that case you can get a DMA handle for each
miniport adapter.

-ali

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"Peter" <x@y> wrote in message news:eRixpgNlIHA.3512(a)TK2MSFTNGP03.phx.gbl...
> Hi!
>
> Is it possible for a miniport driver to allocate more than one DMA
> handles? We are working with a device that supports a multi-function
> device and would like to separate DMA access bewteen these functions by
> using separate DMA handles. While this appears to work with free-build
> NDIS, I see the checked NDIS trigger the assert I show above.
>
> Naturally, the WDK is unclear about the limitations the driver faces with
> calls to NdisMRegisterScatterGatherDma, so any help to clarify this would
> be helpful.
>
> Thanks!
>

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