O Linux reconhece apenas a memória parcial

Question

Eu tentei diferentes distribuições linux (Ubuntu 12.10 Gnome Remix, Fedora 18, Bridge Linux) no meu novo laptop, mas todas elas têm um problema com a memória. Meu laptop tem 4 GB de memória, mas o Ubuntu reconhece apenas 2,4 GB. Obviamente, tanto o BIOS quanto o Windows 8 reconhecem todos os 4GB.

Minha configuração de laptop: Lenovo B590 CPU: Intel Core i5-3210M RAM: Placa-mãe de chipset DDR3-SDRAM de 4 GB: Intel HM77 Express Gráficos integrados: HD Graphics 4000.

Pode ser possível que a memória perdida seja emprestada da Intel HD Graphics? se é verdade, sempre empresta memória máxima fixa!!

Algumas saídas de comandos úteis:

midecode --type memory

Array Handle: 0x000B
Error Information Handle: Not Provided
Total Width: 64 bits
Data Width: 64 bits
Size: 4096 MB
Form Factor: SODIMM
Set: None
Locator: ChannelB-DIMM0
Bank Locator: BANK 2
Type: DDR3
Type Detail: Synchronous
Speed: 1600 MHz
Manufacturer: Hynix/Hyundai
Serial Number: 1A21B5B9
Asset Tag: 9876543210
Part Number: HMT351S6EFR8C-PB  
Rank: Unknown
Configured Clock Speed: 1600 MHz

Saída de free -m :

              total   used    free  shared    buffers     cached
Mem:          2483    1136    1346       0         56        515
-/+ buffers/cache:     563    1919
Swap:         4884       0    4884

Saída de cat /proc/meminfo | grep "Mem*"

MemTotal:        2542664 kB
MemFree:         1373552 kB

Saída de dmesg | grep -i memory

[    0.000000] initial memory mapped: [mem 0x00000000-0x1fffffff]
[    0.000000] Base memory trampoline at [ffff880000097000] 97000 size 24576
[    0.000000] init_memory_mapping: [mem 0x00000000-0x846f1fff]
[    0.000000] init_memory_mapping: [mem 0x100000000-0x11e5fffff]
[    0.000000] Early memory node ranges
[    0.000000] PM: Registered nosave memory: 000000000009d000 - 00000000000a0000
[    0.000000] PM: Registered nosave memory: 00000000000a0000 - 00000000000e0000
[    0.000000] PM: Registered nosave memory: 00000000000e0000 - 0000000000100000
[    0.000000] PM: Registered nosave memory: 0000000020000000 - 0000000020200000
[    0.000000] PM: Registered nosave memory: 0000000040004000 - 0000000040005000
[    0.000000] PM: Registered nosave memory: 00000000846f2000 - 00000000dae9f000
[    0.000000] PM: Registered nosave memory: 00000000dae9f000 - 00000000daf9f000
[    0.000000] PM: Registered nosave memory: 00000000daf9f000 - 00000000dafff000
[    0.000000] PM: Registered nosave memory: 00000000dafff000 - 00000000dfa00000
[    0.000000] PM: Registered nosave memory: 00000000dfa00000 - 00000000f8000000
[    0.000000] PM: Registered nosave memory: 00000000f8000000 - 00000000fc000000
[    0.000000] PM: Registered nosave memory: 00000000fc000000 - 00000000fe800000
[    0.000000] PM: Registered nosave memory: 00000000fe800000 - 00000000fe810000
[    0.000000] PM: Registered nosave memory: 00000000fe810000 - 00000000fec00000
[    0.000000] PM: Registered nosave memory: 00000000fec00000 - 00000000fec01000
[    0.000000] PM: Registered nosave memory: 00000000fec01000 - 00000000fed08000
[    0.000000] PM: Registered nosave memory: 00000000fed08000 - 00000000fed09000
[    0.000000] PM: Registered nosave memory: 00000000fed09000 - 00000000fed10000
[    0.000000] PM: Registered nosave memory: 00000000fed10000 - 00000000fed1a000
[    0.000000] PM: Registered nosave memory: 00000000fed1a000 - 00000000fed1c000
[    0.000000] PM: Registered nosave memory: 00000000fed1c000 - 00000000fed20000
[    0.000000] PM: Registered nosave memory: 00000000fed20000 - 00000000fee00000
[    0.000000] PM: Registered nosave memory: 00000000fee00000 - 00000000fee01000
[    0.000000] PM: Registered nosave memory: 00000000fee01000 - 00000000ffc20000
[    0.000000] PM: Registered nosave memory: 00000000ffc20000 - 0000000100000000
[    0.000000] Memory: 2515460k/4691968k available (6711k kernel code, 2027016k absent, 149492k reserved, 6459k data, 928k init)
[    0.000000] please try 'cgroup_disable=memory' option if you don't want memory cgroups
[    0.001851] Initializing cgroup subsys memory
[    0.522565] Freeing initrd memory: 23680k freed
[    1.430344] Freeing unused kernel memory: 928k freed
[    1.433360] Freeing unused kernel memory: 1472k freed
[    1.435653] Freeing unused kernel memory: 1124k freed
[    1.471316] pci 0000:00:00.0: >detected 65536K stolen memory
[   16.146844] Non-volatile memory driver v1.3

Linux antonio-Notebook 3.5.0-17-generic #28-Ubuntu SMP
Tue Oct 9 19:31:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

dmesg | grep BIOS-e820

[    0.000000] BIOS-e820: [mem 0x0000000000000000-0x000000000009cfff] usable
[    0.000000] BIOS-e820: [mem 0x000000000009d000-0x000000000009ffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000000100000-0x000000001fffffff] usable
[    0.000000] BIOS-e820: [mem 0x0000000020000000-0x00000000201fffff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000020200000-0x0000000040003fff] usable
[    0.000000] BIOS-e820: [mem 0x0000000040004000-0x0000000040004fff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000040005000-0x00000000846f1fff] usable
[    0.000000] BIOS-e820: [mem 0x00000000846f2000-0x00000000dae9efff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000dae9f000-0x00000000daf9efff] ACPI NVS
[    0.000000] BIOS-e820: [mem 0x00000000daf9f000-0x00000000daffefff] ACPI data
[    0.000000] BIOS-e820: [mem 0x00000000dafff000-0x00000000df9fffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000f8000000-0x00000000fbffffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fe800000-0x00000000fe80ffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fec00000-0x00000000fec00fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fed08000-0x00000000fed08fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fed10000-0x00000000fed19fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fed1c000-0x00000000fed1ffff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000fee00000-0x00000000fee00fff] reserved
[    0.000000] BIOS-e820: [mem 0x00000000ffc20000-0x00000000ffffffff] reserved
[    0.000000] BIOS-e820: [mem 0x0000000100000000-0x000000011e5fffff] usable