I just experienced this bug (switched to Intrepid yesterday, the bug never appeared with Hardy):

I surfed in the internet and suddenly everything was frozen. I changed the terminal and then a

[time...] ata3:Softreset failed (device not ready)

appeared. I switched back to X and then after a few seconds everything woke up again. On console at F8 was very much output:"
[  361.492541] ata3.00: exception Emask 0x0 SAct 0xf SErr 0x0 action 0x6 frozen
[  361.492608] ata3.00: cmd 60/08:00:67:9b:28/00:00:05:00:00/40 tag 0 ncq 4096 in
[  361.492611]          res 40/00:00:00:4f:c2/00:00:00:00:00/00 Emask 0x4 (timeout)
[  361.492694] ata3.00: status: { DRDY }
[  361.492737] ata3.00: cmd 60/08:08:5f:04:78/00:00:1a:00:00/40 tag 1 ncq 4096 in
[  361.492740]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[  361.492822] ata3.00: status: { DRDY }
[  361.492865] ata3.00: cmd 60/18:10:c7:2a:80/00:00:0c:00:00/40 tag 2 ncq 12288 in
[  361.492868]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[  361.492949] ata3.00: status: { DRDY }
[  361.492992] ata3.00: cmd 60/08:18:17:81:6c/00:00:1a:00:00/40 tag 3 ncq 4096 in
[  361.492995]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[  361.493082] ata3.00: status: { DRDY }
[  361.493128] ata3: hard resetting link
[  361.976041] ata3: softreset failed (device not ready)
[  361.976096] ata3: failed due to HW bug, retry pmp=0
[  362.140043] ata3: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[  362.150871] ata3.00: configured for UDMA/133
[  362.150912] ata3: EH complete
[  362.214653] sd 2:0:0:0: [sda] 488397168 512-byte hardware sectors (250059 MB)
[  362.268441] sd 2:0:0:0: [sda] Write Protect is off
[  362.268458] sd 2:0:0:0: [sda] Mode Sense: 00 3a 00 00
[  362.401303] sd 2:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
"

I have ahci enabled in BIOS in order to use ncq, which works afaik. I use an Intrepid System (upgraded from Hardy), AMD64 dual core, 3 GB RAM and a Gigabyte Mainboard (GA-MA78G-DS3H) version 1 with a BIOS update to version F4.

If I can help, just ask. 
Thanks!

PS: The output of "lspci":
$ lspci
00:00.0 Host bridge: Advanced Micro Devices [AMD] RS780 Host Bridge
00:01.0 PCI bridge: Advanced Micro Devices [AMD] RS780 PCI to PCI bridge (int gfx)
00:0a.0 PCI bridge: Advanced Micro Devices [AMD] RS780 PCI to PCI bridge (PCIE port 5)
00:11.0 SATA controller: ATI Technologies Inc SB700/SB800 SATA Controller [AHCI mode]
00:12.0 USB Controller: ATI Technologies Inc SB700/SB800 USB OHCI0 Controller
00:12.1 USB Controller: ATI Technologies Inc SB700 USB OHCI1 Controller
00:12.2 USB Controller: ATI Technologies Inc SB700/SB800 USB EHCI Controller
00:13.0 USB Controller: ATI Technologies Inc SB700/SB800 USB OHCI0 Controller
00:13.1 USB Controller: ATI Technologies Inc SB700 USB OHCI1 Controller
00:13.2 USB Controller: ATI Technologies Inc SB700/SB800 USB EHCI Controller
00:14.0 SMBus: ATI Technologies Inc SBx00 SMBus Controller (rev 3a)
00:14.1 IDE interface: ATI Technologies Inc SB700/SB800 IDE Controller
00:14.2 Audio device: ATI Technologies Inc SBx00 Azalia (Intel HDA)
00:14.3 ISA bridge: ATI Technologies Inc SB700/SB800 LPC host controller
00:14.4 PCI bridge: ATI Technologies Inc SBx00 PCI to PCI Bridge
00:14.5 USB Controller: ATI Technologies Inc SB700/SB800 USB OHCI2 Controller
00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration
00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller
00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control
01:05.0 VGA compatible controller: ATI Technologies Inc Radeon HD 3200 Graphics
01:05.1 Audio device: ATI Technologies Inc RS780 Azalia controller
02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 02)
03:0e.0 FireWire (IEEE 1394): Texas Instruments TSB43AB23 IEEE-1394a-2000 Controller (PHY/Link)