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Re: Prefetchable flag in BAR



I have a question which is kind of related to this discussion.
 
What is the biggest BAR that people have been able to allocate
in Intel based systems?  I have played around with our NICS, trying
to allocate 512 Mbytes or 1 Gbyte at BAR0 in a couple of older
systems in my lab.  Some machines map those requests correctly,
some don't map them at all.
 
a) Is it the system BIOS that controls this?  If so, would different
BIOS on the same machine result in different mapping results?
b) Has anyone ever successfully mapped over 1G of memory in any
Intel system?  If so, what system, and how much could you map?
 
Thanks in advance,
 
Brian Breuer
Videopropulsion
----- Original Message -----
Sent: Thursday, July 18, 2002 10:10 PM
Subject: Re: Prefetchable flag in BAR


We have had problems if the card allocates too much memory that you run
out of kernel buffers.  But we mainly saw that problem on NT4.  If that is
your problem, then there is some registry setting that you can change to
use more kernel buffers.

On Fri, 19 Jul 2002 kseom@samsung.co.kr wrote:

> Hi, experts:
>
> We're developing PCI and CardBus product, which has on-board memory that is configured as "Prefetchable" in BAR.
> When we insert the card to Win2K PC, it was OK. But the requested memory can not be allocated for Win98 PC.
>
> I suspect that the reason is that Win98 does not recognize the "Prefetchable" in BAR.
> If you had the same experience, could you share the info how you solved it?
>
> Regards,
> Richard Eom.
>

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