Comment 68 for bug 539467

Acer ASPIRE 3820 TG, unplugging power gives this in dmesg:

[ 857.224924] EXT4-fs (sda3): re-mounted. Opts: errors=remount-ro,commit=600
[ 869.230484] EXT4-fs (sda3): re-mounted. Opts: errors=remount-ro,commit=0
[ 869.416988] ata1: exception Emask 0x10 SAct 0x0 SErr 0x50000 action 0xe frozen
[ 869.416991] ata1: irq_stat 0x00400000, PHY RDY changed
[ 869.416993] ata1: SError: { PHYRdyChg CommWake }
[ 869.416998] ata1: hard resetting link
[ 870.170801] ata1: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[ 870.175479] ata1.00: configured for UDMA/133
[ 870.175487] ata1: EH complete

This can be avoided by changing AHCI to IDE mode in bios.