Bon, j'ai jeté un oeil sur mon dmesg et j'ai repéré quelques « trous », en voici :

[    3.676751] scsi6 : pata_atiixp
[    3.679113] scsi7 : pata_atiixp
[    3.679637] ata7: PATA max UDMA/100 cmd 0x1f0 ctl 0x3f6 bmdma 0xff00 irq 14
[    3.679639] ata8: PATA max UDMA/100 cmd 0x170 ctl 0x376 bmdma 0xff08 irq 15
[   34.784130] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
[   34.784134] ata1.00: failed command: IDENTIFY PACKET DEVICE
[   34.784138] ata1.00: cmd a1/00:01:00:00:00/00:00:00:00:00/00 tag 0 pio 512 in
[   34.784139]          res 40/00:03:00:00:00/00:00:00:00:00/a0 Emask 0x4 (timeout)
[   34.784141] ata1.00: status: { DRDY }
[   34.784145] ata1: hard resetting link
[   35.244049] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[   36.046778] ata1.00: configured for PIO4
[   36.847517] ata1: EH complete

[   46.227120] usbcore: registered new interface driver usblp
[   46.229158] udev-configure-printer[705]: MFG:HP MDL:Deskjet 5900 series SERN:CN67K1T0BT04KF serial:CN67K1T0BT04KF
[   47.723952] udev-configure-printer[705]: failed to connect to CUPS server; giving up
[   52.145713] Adding 1441788k swap on /dev/mapper/vg_fixe-lv_swap.  Priority:0 extents:1 across:1441788k 
[   52.395781] systemd-fsck[725]: /dev/sda1 : propre, 46/128016 fichiers, 89196/512000 blocs
[   52.520815] EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: (null)
[   52.524859] SELinux: initialized (dev sda1, type ext4), uses xattr
[   73.760065] ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
[   73.760069] ata1.00: failed command: IDENTIFY PACKET DEVICE
[   73.760073] ata1.00: cmd a1/00:01:00:00:00/00:00:00:00:00/00 tag 0 pio 512 in
[   73.760074]          res 40/00:03:00:00:00/00:00:00:00:00/a0 Emask 0x4 (timeout)
[   73.760076] ata1.00: status: { DRDY }
[   73.760080] ata1: hard resetting link
[   74.220058] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[   75.022558] ata1.00: configured for PIO4
[   75.823232] ata1: EH complete

et

[   78.925181] SELinux: initialized (dev rpc_pipefs, type rpc_pipefs), uses genfs_contexts
[   79.713264] r8169 0000:03:00.0: p10p1: link up
[   79.716018] ADDRCONF(NETDEV_CHANGE): p10p1: link becomes ready
[   84.522037] hda-intel: IRQ timing workaround is activated for card #1. Suggest a bigger bdl_pos_adj.
[   90.594053] p10p1: no IPv6 routers present
[   93.324662] fuse init (API version 7.16)
[   93.330169] SELinux: initialized (dev fuse, type fuse), uses genfs_contexts
[   93.361592] SELinux: initialized (dev fusectl, type fusectl), uses genfs_contexts

Bon bah je vais creuser ce point là : « ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen »

[edit] : @tsly et alphad : balancez cette commande chez vous et checkez s'il y a aussi des trous de ce genre.

dmesg > ~/Bureau/dmesg.txt