Re: Macbook 4G only see 3G

From: Trenton D. Adams
Date: Thu Jun 11 2009 - 00:48:16 EST

On Wed, Jun 10, 2009 at 10:23 PM, Robert Hancock<hancockrwd@xxxxxxxxx> wrote:
> Trenton D. Adams wrote:
>> dmtdamac ~ # dmesg
>> Linux version 2.6.30-rc7-dirty (root@tdamac) (gcc version 4.3.2
>> (Gentoo 4.3.2-r3 p1.6, pie-10.1.5) ) #3 SMP Fri Jun 5 21:24:29 MDT
>> 2009
>> Command line: root=/dev/ram0 init=/linuxrc real_root=/dev/s/sys dolvm
>> hung_task_show_state=1
>> KERNEL supported cpus:
>>  Intel GenuineIntel
>>  AMD AuthenticAMD
>>  Centaur CentaurHauls
>> BIOS-provided physical RAM map:
>>  BIOS-e820: 0000000000000000 - 000000000009fc00 (usable)
>>  BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)
>>  BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved)
>>  BIOS-e820: 0000000000100000 - 00000000be08c000 (usable)
>>  BIOS-e820: 00000000be08c000 - 00000000be28d000 (ACPI NVS)
>>  BIOS-e820: 00000000be28d000 - 00000000beebe000 (ACPI data)
>>  BIOS-e820: 00000000beebe000 - 00000000beeef000 (ACPI NVS)
>>  BIOS-e820: 00000000beeef000 - 00000000bef00000 (ACPI data)
>>  BIOS-e820: 00000000bef00000 - 00000000c0000000 (reserved)
>>  BIOS-e820: 00000000f0000000 - 00000000f4000000 (reserved)
>>  BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved)
>>  BIOS-e820: 00000000fed14000 - 00000000fed1a000 (reserved)
>>  BIOS-e820: 00000000fed1c000 - 00000000fed20000 (reserved)
>>  BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved)
>>  BIOS-e820: 00000000ffe00000 - 0000000100000000 (reserved)
> The e820 map is the way that the BIOS tells us what memory is available.
>  Here it's only showing about 3040MB of usable memory, all below 4GB. The
> usual way that it should work with 4GB of RAM is that the portion of the
>  memory corresponding to the address space occupied for PCI devices, etc.
>  gets relocated above 4GB. However either the chipset in your machine
> doesn't support memory hole remapping, the BIOS doesn't bother to use it or
> it doesn't bother to tell Linux where it is..
> Do you know if Mac OS X is actually use all 4GB, or is it doing the "well,
> we can see there's actually 4GB installed but we won't mention that we can't
> use it all" trick, like some Windows does?

That is very well possible. It did appear to have over 3G free, if I
recall correctly. I'll try booting into Mac OS X again and see.

> Your dmesg shows your chiset is 945GM.
> ==
> intelfb 0000:00:02.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16
> intelfb: 00:02.0: Intel(R) 945GM, aperture size 256MB, stolen memory 16124kB
> intelfb: Non-CRT device is enabled ( LVDS port ). Disabling mode switching.
> intelfb: Video mode must be programmed at boot time.
> ==
> As far as I can found in English/Japanese forum, 945GM/PM? series can't handle
> 4G memory. (Then, 64bit Vista can't handle it, either)

That's my graphics card though, not my motherboard chipset. The
chipset is ICH7.
tdamac ~ # lspci

00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML
and 945GT Express Memory Controller Hub (rev 03)
00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS,
943/940GML Express Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME,
943/940GML Express Integrated Graphics Controller (rev 03)
00:07.0 Performance counters: Intel Corporation Device 27a3 (rev 03)
00:1b.0 Audio device: Intel Corporation 82801G (ICH7 Family) High
Definition Audio Controller (rev 02)
00:1c.0 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express
Port 1 (rev 02)
00:1c.1 PCI bridge: Intel Corporation 82801G (ICH7 Family) PCI Express
Port 2 (rev 02)
00:1d.0 USB Controller: Intel Corporation 82801G (ICH7 Family) USB
UHCI Controller #1 (rev 02)
00:1d.1 USB Controller: Intel Corporation 82801G (ICH7 Family) USB
UHCI Controller #2 (rev 02)
00:1d.2 USB Controller: Intel Corporation 82801G (ICH7 Family) USB
UHCI Controller #3 (rev 02)
00:1d.3 USB Controller: Intel Corporation 82801G (ICH7 Family) USB
UHCI Controller #4 (rev 02)
00:1d.7 USB Controller: Intel Corporation 82801G (ICH7 Family) USB2
EHCI Controller (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e2)
00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface
Bridge (rev 02)
00:1f.1 IDE interface: Intel Corporation 82801G (ICH7 Family) IDE
Controller (rev 02)
00:1f.2 IDE interface: Intel Corporation 82801GBM/GHM (ICH7 Family)
SATA IDE Controller (rev 02)
00:1f.3 SMBus: Intel Corporation 82801G (ICH7 Family) SMBus Controller (rev 02)
01:00.0 Ethernet controller: Marvell Technology Group Ltd. 88E8053
PCI-E Gigabit Ethernet Controller (rev 22)
02:00.0 Network controller: Atheros Communications Inc. AR5418
802.11abgn Wireless PCI Express Adapter (rev 01)
03:03.0 FireWire (IEEE 1394): Agere Systems FW323 (rev 61)
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