From: Matt Porter <mporter@kernel.crashing.org>
To: Matt Sexton <sexton@mc.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: DRAM and PCI devices at same physical address
Date: Sat, 26 Jun 2004 20:26:48 -0700 [thread overview]
Message-ID: <20040626202648.B29650@home.com> (raw)
In-Reply-To: <1088198580.29697.62.camel@dhcp_client-120-140>; from sexton@mc.com on Fri, Jun 25, 2004 at 05:23:00PM -0400
On Fri, Jun 25, 2004 at 05:23:00PM -0400, Matt Sexton wrote:
> I have a dual Xeon system with the Lindenhurst (E7710) chip set and 1 GB
> of memory. In order to reserve a very large block of memory for a
> (user-space) device driver I am writing, I pass "mem=XX" to the kernel
> at boot time. Unfortunately, /proc/pci shows two devices now appearing
> in the reserved upper memory range.
<snip>
> The devices always appear right after the limit I specify on the kernel
> boot line. If I specify "mem=512M", then the first device appears at
> 0x20000000. If I specify nothing, then it appears at 0x40000000. All
> other PCI devices show up at addresses of 0xDD000000 and above.
>
> Is there any way to prevent these devices from showing up in the
> physical address range of my reserved memory?
You could try using reserve_bootmem() to reserve your driver memory.
> Should they be appearing there at all? Does Linux make any guarantees
> when there is more physical memory than specified by "mem=" ?
Depends on the arch, I don't know what ia32 does.
-Matt
next prev parent reply other threads:[~2004-06-27 3:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-06-25 21:23 DRAM and PCI devices at same physical address Matt Sexton
2004-06-27 3:26 ` Matt Porter [this message]
2004-06-28 15:51 ` Matt Sexton
2004-06-28 16:22 ` Matt Porter
2004-06-28 19:27 ` Ross Biro
2004-06-29 14:31 ` Matt Sexton
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