2007-06-29 20:47:35

by Frank Fiene

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Subject: Kernel doesn't recognize complete memory

Lenovo Z61p, Intel Core2 Duo T7200

I have 4GB RAM installed and BIOS recognize 4GB RAM.
Linux kernel (Ubuntu-7.04, 32bit-PAE and 64bit, openSUSE-10.2 32bit-PAE
and 64bit) tells me: only 3GB of RAM are installed.

Any other user with a 4GB Thinkpad? tytso?

What can i do? Please help!

Regards
Frank


2007-06-29 23:19:19

by Robert Hancock

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Subject: Re: Kernel doesn't recognize complete memory

Frank Fiene wrote:
> Lenovo Z61p, Intel Core2 Duo T7200
>
> I have 4GB RAM installed and BIOS recognize 4GB RAM.
> Linux kernel (Ubuntu-7.04, 32bit-PAE and 64bit, openSUSE-10.2 32bit-PAE
> and 64bit) tells me: only 3GB of RAM are installed.
>
> Any other user with a 4GB Thinkpad? tytso?
>
> What can i do? Please help!
>
> Regards
> Frank

Please post your bootup dmesg output. If your chipset doesn't support
memory remapping above 4GB or the BIOS doesn't enable it, you won't be
able to use all 4GB of memory.

--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from [email protected]
Home Page: http://www.roberthancock.com/

2007-06-30 00:34:44

by Russell Harmon

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Subject: Re: Kernel doesn't recognize complete memory

http://kerneltrap.org/node/2450/7217 is likely your problem, although
why you can see 3gb instead of only 1gb of ram, idk... maybe something
ubuntu specific...

On 6/29/07, Frank Fiene <[email protected]> wrote:
> Lenovo Z61p, Intel Core2 Duo T7200
>
> I have 4GB RAM installed and BIOS recognize 4GB RAM.
> Linux kernel (Ubuntu-7.04, 32bit-PAE and 64bit, openSUSE-10.2 32bit-PAE
> and 64bit) tells me: only 3GB of RAM are installed.
>
> Any other user with a 4GB Thinkpad? tytso?
>
> What can i do? Please help!
>
> Regards
> Frank
> -
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>

2007-06-30 01:08:13

by Matti Aarnio

[permalink] [raw]
Subject: Re: Kernel doesn't recognize complete memory

On Fri, Jun 29, 2007 at 10:25:26PM +0200, Frank Fiene wrote:
> Lenovo Z61p, Intel Core2 Duo T7200
>
> I have 4GB RAM installed and BIOS recognize 4GB RAM.
> Linux kernel (Ubuntu-7.04, 32bit-PAE and 64bit, openSUSE-10.2 32bit-PAE
> and 64bit) tells me: only 3GB of RAM are installed.

With AMD's Athlon64 the answer would be "look into BIOS settings,
(re)map 3-4 GB memory above 4 GB address mark"..

The PCI-bus and all IO devices in it needs memory space within
the first 4 GB of physical address space. Some devices support
64-bit addresses in which case they can access whole physical
memory, most probably don't, meaning that they can access only
memory in lowest 4 GB part of the space.

Original 8088 PC had 20 bit address space, and "huge" megabyte
of address space. Then came 286 AT era with 24 bit addresses
and "whopping" 16 megabyte address space.. then came 386 and
finally true 32-bit addresses -- but ISA-space VGA aperture had
to be in there still.. and to gain access to of that memory
located "under" that VGA aperture, there was mapping...

Now the VGA aperture mapping is no more, but the PCI has similar
requirements - albeit with bigger apertures.


So, what does your BIOS have hidden in "advanced" menus (most likely) ?
Something about "remap (PCI?) memory above 4 GB" ?


> Any other user with a 4GB Thinkpad? tytso?
>
> What can i do? Please help!
>
> Regards
> Frank

Regards, Matti Aarnio

2007-06-30 17:47:18

by Frank Fiene

[permalink] [raw]
Subject: Re: Kernel doesn't recognize complete memory

On Samstag, 30. Juni 2007, Robert Hancock wrote:
> Frank Fiene wrote:
> > Lenovo Z61p, Intel Core2 Duo T7200
> >
> > I have 4GB RAM installed and BIOS recognize 4GB RAM.
> > Linux kernel (Ubuntu-7.04, 32bit-PAE and 64bit, openSUSE-10.2
> > 32bit-PAE and 64bit) tells me: only 3GB of RAM are installed.
> >
> > Any other user with a 4GB Thinkpad? tytso?
> >
> > What can i do? Please help!
> >
> > Regards
> > Frank
>
> Please post your bootup dmesg output. If your chipset doesn't support
> memory remapping above 4GB or the BIOS doesn't enable it, you won't
> be able to use all 4GB of memory.

Here is me dmesg output, fist 400 lines.

Regards
Frank


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2007-06-30 18:25:16

by Robert Hancock

[permalink] [raw]
Subject: Re: Kernel doesn't recognize complete memory

Frank Fiene wrote:
> On Samstag, 30. Juni 2007, Robert Hancock wrote:
>> Frank Fiene wrote:
>>> Lenovo Z61p, Intel Core2 Duo T7200
>>>
>>> I have 4GB RAM installed and BIOS recognize 4GB RAM.
>>> Linux kernel (Ubuntu-7.04, 32bit-PAE and 64bit, openSUSE-10.2
>>> 32bit-PAE and 64bit) tells me: only 3GB of RAM are installed.
>>>
>>> Any other user with a 4GB Thinkpad? tytso?
>>>
>>> What can i do? Please help!
>>>
>>> Regards
>>> Frank
>> Please post your bootup dmesg output. If your chipset doesn't support
>> memory remapping above 4GB or the BIOS doesn't enable it, you won't
>> be able to use all 4GB of memory.
>
> Here is me dmesg output, fist 400 lines.

BIOS-provided physical RAM map:
BIOS-e820: 0000000000000000 - 000000000009f000 (usable)
BIOS-e820: 000000000009f000 - 00000000000a0000 (reserved)
BIOS-e820: 00000000000dc000 - 0000000000100000 (reserved)
BIOS-e820: 0000000000100000 - 00000000bfed0000 (usable)
BIOS-e820: 00000000bfed0000 - 00000000bfedf000 (ACPI data)
BIOS-e820: 00000000bfedf000 - 00000000bff00000 (ACPI NVS)
BIOS-e820: 00000000bff00000 - 00000000c0000000 (reserved)
BIOS-e820: 00000000f0000000 - 00000000f4000000 (reserved)
BIOS-e820: 00000000fec00000 - 00000000fec10000 (reserved)
BIOS-e820: 00000000fed00000 - 00000000fed00400 (reserved)
BIOS-e820: 00000000fed14000 - 00000000fed1a000 (reserved)
BIOS-e820: 00000000fed1c000 - 00000000fed90000 (reserved)
BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
BIOS-e820: 00000000ff800000 - 0000000100000000 (reserved)

Yes, that's the problem. Your BIOS/chipset only provides about 3070MB of
usable RAM to the OS. Unless there is a memory remap option in the BIOS
that you can enable, there's not much you can do about it.

--
Robert Hancock Saskatoon, SK, Canada
To email, remove "nospam" from [email protected]
Home Page: http://www.roberthancock.com/


2007-07-01 03:54:56

by Matthew Garrett

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Subject: Re: Kernel doesn't recognize complete memory

The 945 chipset used in the Z61 can only address 4GB of physical address
space and your BIOS is using some of this for PCI and other bits of
hardware. That only leaves 3GB for RAM. I believe that this restriction
is mentioned on the IBM website somewhere.

--
Matthew Garrett | [email protected]