Ok, thanks for the prompt reply and the notice for the cc: :)
I'm using libata and ata_piix now.
My disk is seen as "sda" and a lshw is reporting the controler as using "ata_piix" :
# lshw -c STORAGE
*-ide
description: IDE interface
product: 82371AB/EB/MB PIIX4 IDE
vendor: Intel Corporation
physical id: 7.1
bus info: pci@0000:00:07.1
logical name: scsi0
logical name: scsi1
version: 01
width: 32 bits
clock: 33MHz
capabilities: ide bus_master emulated
configuration: driver=ata_piix latency=0
But fdisk always recognize the disk as 136.8Gb :
# fdisk -l
Disk /dev/sda: 136.8 GB, 136899993600 bytes
16 heads, 63 sectors/track, 265260 cylinders
Units = cylinders of 1008 * 512 = 516096 bytes
Disk identifier: 0xd7267427
Device Boot Start End Blocks Id System
/dev/sda1 * 1 204 102815+ 83 Linux
/dev/sda2 205 2236 1024128 82 Linux swap / Solaris
/dev/sda3 2237 20805 9358776 83 Linux
Here is the new kernel config file : http://pastebin.com/f65fd472b