Depends on HAL. It is very possible that on non-PAE x86 machine map registers are no-op for PCI.
I saw once an NT4 driver source for a PCI card which used MmGetPhysicalAddress for DMA instead of map registers and common buffers.
It worked, though this practice is nasty.
Max
----- Original Message -----
From: “Ta H.”
To: “NT Developers Interest List”
Sent: Saturday, April 20, 2002 2:13 AM
Subject: [ntdev] Re: DMA for Read/Write simultaneously [Revisit]
> Hmm, now I feel it has nothing to do with the numbers of the DMA adapters
> but with the numbers of the map registers. As Max suggested earlier, I
> should ask for unlimited map registers. How does Windows implement the
> map registers for x86?
>
> Thanks
>
> Ta H.
>
>
> >From: “Peter Viscarola”
> >Reply-To: “NT Developers Interest List”
> >To: “NT Developers Interest List”
> >Subject: [ntdev] Re: DMA for Read/Write simultaneously [Revisit]
> >Date: Fri, 19 Apr 2002 12:27:19 -0400
> >
> >“Ta H.” wrote in message news:xxxxx@ntdev…
> > >
> > > write is in effect, that read won’t start until I free map registers in
> >my
> > > write DPC; ie, the wtite DMA is done.
> > >
> >
> >Did you try calling IoAllocateDmaAdapter twice? Once for each Device
> >Object? And using one adapter for read and one for write?
> >
> >I don’t think that’s the problem, frankly, but it’s easy and worth a try…
> >
> >Peter
> >OSR
> >
> >
> >
> >
> >
> >—
> >You are currently subscribed to ntdev as: xxxxx@hotmail.com
> >To unsubscribe send a blank email to %%email.unsub%%
>
>
>
>
> _________________________________________________________________
> Join the world’s largest e-mail service with MSN Hotmail.
> http://www.hotmail.com
>
>
> —
> You are currently subscribed to ntdev as: xxxxx@storagecraft.com
> To unsubscribe send a blank email to %%email.unsub%%
>