2.6.27-7-generic not detecting 4GB RAM

[Ronny Bangsund]

Binary package hint: linux-image-generic

Only 2.7GB RAM detected on a 64-bit system installed from a Kubuntu 8.10 Beta 64-bit CD.

Motherboard: P5B-VM.
CPU: Intel Core 2 Duo E6600.
RAM: 2x2GB.

The results from uname -a:
Linux vulbuzo 2.6.27-7-generic #1 SMP Fri Oct 17 22:24:30 UTC 2008 x86_64 GNU/Linux

Free reports:
Mem: 2830860 994552 1836308 0 31468 498524

Other 64-bit operating systems and earlier 64-bit Ubuntu releases have detected the full amount just fine, most recently Kubuntu 8.04 LTS.

[Victor Cherkassky (vcherkassky)]

I have exactly the same issue on 32 bit Ubuntu Intrepid Ibex 8.10.
My Samsung R60 - XY01 has Intel Core 2 Duo T5250 and BIOS detects full 4Gb.
I tried compiling kernel with PAE support (4GB and 64GB turned on) from 2.6.27 source.

Now i'm running 2.6.27-7-server, was running 2.6.27-7-generic.

free:
                    total used free shared buffers cached
Mem: 2850784 2764372 86412 0 89668 855304

Still 4GB are detected as 2.7Gb.

Here is dmidecode part (don't know if it says something):
..............................
Handle 0x000A, DMI type 16, 15 bytes
Physical Memory Array
 Location: System Board Or Motherboard
 Use: System Memory
 Error Correction Type: None
 Maximum Capacity: 1 GB
 Error Information Handle: Not Provided
 Number Of Devices: 2

Handle 0x000B, DMI type 17, 27 bytes
Memory Device
 Array Handle: 0x000A
 Error Information Handle: No Error
 Total Width: 64 bits
 Data Width: 64 bits
 Size: 2048 MB
 Form Factor: DIMM
 Set: 1
 Locator: J400
 Bank Locator: Channel A0
 Type: DRAM
 Type Detail: Synchronous
 Speed: Unknown
 Manufacturer: Not Specified
 Serial Number: Not Specified
 Asset Tag: Not Specified
 Part Number: Not Specified

Handle 0x000C, DMI type 17, 27 bytes
Memory Device
 Array Handle: 0x000A
 Error Information Handle: No Error
 Total Width: 64 bits
 Data Width: 64 bits
 Size: 2048 MB
 Form Factor: DIMM
 Set: 3
 Locator: J501
 Bank Locator: Channel B0
 Type: DRAM
 Type Detail: Synchronous
 Speed: Unknown
 Manufacturer: Not Specified
 Serial Number: Not Specified
 Asset Tag: Not Specified
 Part Number: Not Specified

Handle 0x000D, DMI type 18, 23 bytes
32-bit Memory Error Information
 Type: OK
 Granularity: Unknown
 Operation: Unknown
 Vendor Syndrome: Unknown
 Memory Array Address: Unknown
 Device Address: Unknown
 Resolution: Unknown

Handle 0x000E, DMI type 19, 15 bytes
Memory Array Mapped Address
 Starting Address: 0x00000000000
 Ending Address: 0x000FFFFFFFF
 Range Size: 4 GB
 Physical Array Handle: 0x000A
 Partition Width: 0

Handle 0x000F, DMI type 20, 19 bytes
Memory Device Mapped Address
 Starting Address: 0x00000000000
 Ending Address: 0x0007FFFFFFF
 Range Size: 2 GB
 Physical Device Handle: 0x000B
 Memory Array Mapped Address Handle: 0x000E
 Partition Row Position: 2
 Interleave Position: 1
 Interleaved Data Depth: 6
.....................................

[Ronny Bangsund (ronnyb)]

Problem gone, probably a motherboard issue. Here's the trouble I went through to fix it:
1.Reset BIOS with that little jumper on the motherboard.
2.Upgrade BIOS. This gave me PAE settings (didn't find any before!).
3.Reset to defaults.
4.Adjusted the above-mentioned PAE settings till memory was reported correctly both in BIOS and various operating systems (try with live CDs).

[Victor Cherkassky (vcherkassky)]

Yeah, the problem is BIOS. I realized that after my auto RAM check saw only 2800 (thought that one Memory module is burned, but no: inserting 1Gb instead of it causes the same effect).
The problem is i can't now properly update my BIOS because latest version is EXE for WinXP/Wista wanting to check battery state before doing something, therefore not working under WinPE. I'l try not the latest one, but newer than my current (under DOS), maybe something will change. I really don't want to install this peace of s...oftware :) (win) on my notebook.

I think we can now close this bug.

[Victor Cherkassky (vcherkassky)]

This bug is not linux bug. It's a hardware trouble.