Lots of con-current I/O = resets SATA link? (2.6.25.10)

[Justin Piszcz <jpiszcz@lucidpixels.com>]

I've read the best way to 'deal' with this issue is to turn off apic/acpi 
etc, is there any downside to turning them off?  Particularly APIC for IRQ 
routing?

This happens on drives on both the Intel 965 chipset motherboard ports and 
PCI-e x1 cards, and the cables are not the issue (the cables with 12 other 
150 raptors have no issues) (same cables I used with them)).

With NCQ on or OFF it occurs.

$ ls
0/  10/  12/  14/  16/  18/  2/   3/  5/  7/  9/   runtest.sh*
1/  11/  13/  15/  17/  19/  20/  4/  6/  8/  linux-2.6.25.10.tar

$ cat runtest.sh
#!/bin/bash

for i in `seq 0 20`
do
   cd $i
   tar xf ../linux-2.6.25.10.tar &
   cd ..
done

With NCQ off (earlier) (from just heavy I/O on the raid5):
Jul  5 11:50:06 p34 kernel: [112161.433913] ata6.00: exception Emask 0x0 SAct
0x0 SErr 0x0 action 0x2 frozen
Jul  5 11:50:06 p34 kernel: [112161.433923] ata6.00: cmd
b0/d8:00:00:4f:c2/00:00:00:00:00/00 tag 0
Jul  5 11:50:06 p34 kernel: [112161.433924]          res
40/00:ff:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
Jul  5 11:50:06 p34 kernel: [112161.433927] ata6.00: status: { DRDY }
Jul  5 11:50:06 p34 kernel: [112161.736858] ata6: soft resetting link
Jul  5 11:50:07 p34 kernel: [112161.889840] ata6: SATA link up 3.0 Gbps (SStatus
123 SControl 300)
Jul  5 11:50:07 p34 kernel: [112161.911418] ata6.00: configured for UDMA/133
Jul  5 11:50:07 p34 kernel: [112161.656792] sd 5:0:0:0: [sdf] Write Protect is
off
Jul  5 11:50:07 p34 kernel: [112161.656797] sd 5:0:0:0: [sdf] Mode Sense: 00 3a
00 00
Jul  5 11:50:07 p34 kernel: [112161.659296] sd 5:0:0:0: [sdf] Write cache:
enabled, read cache: enabled, doesn't support DPO or FUA

With NCQ on (with the test shown above):
[115786.990237] ata6.00: exception Emask 0x0 SAct 0x3ffff SErr 0x0 action 0x2 frozen
[115786.990247] ata6.00: cmd 60/80:00:bf:07:94/00:00:10:00:00/40 tag 0 ncq 65536 in
[115786.990249]          res 40/00:00:00:00:00/00:00:00:00:00/a0 Emask 0x4 (timeout)
[115786.990254] ata6.00: status: { DRDY }
[115786.990259] ata6.00: cmd 60/88:08:b7:ee:c1/01:00:1d:00:00/40 tag 1 ncq 200704 in
[115786.990261]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990265] ata6.00: status: { DRDY }
[115786.990270] ata6.00: cmd 60/f8:10:bf:eb:c1/02:00:1d:00:00/40 tag 2 ncq 389120 in
[115786.990271]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990275] ata6.00: status: { DRDY }
[115786.990280] ata6.00: cmd 60/c0:18:3f:e8:c1/01:00:1d:00:00/40 tag 3 ncq 229376 in
[115786.990282]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990286] ata6.00: status: { DRDY }
[115786.990291] ata6.00: cmd 60/c0:20:ff:e9:c1/01:00:1d:00:00/40 tag 4 ncq 229376 in
[115786.990293]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990297] ata6.00: status: { DRDY }
[115786.990302] ata6.00: cmd 61/08:28:0f:c6:b6/00:00:1f:00:00/40 tag 5 ncq 4096 out
[115786.990303]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990307] ata6.00: status: { DRDY }
[115786.990312] ata6.00: cmd 61/10:30:df:b0:17/00:00:01:00:00/40 tag 6 ncq 8192 out
[115786.990313]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990318] ata6.00: status: { DRDY }
[115786.990323] ata6.00: cmd 61/10:38:4f:88:79/00:00:03:00:00/40 tag 7 ncq 8192 out
[115786.990324]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990328] ata6.00: status: { DRDY }
[115786.990333] ata6.00: cmd 61/10:40:3f:18:95/00:00:05:00:00/40 tag 8 ncq 8192 out
[115786.990335]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990339] ata6.00: status: { DRDY }
[115786.990344] ata6.00: cmd 61/08:48:d7:f6:a9/00:00:06:00:00/40 tag 9 ncq 4096 out
[115786.990345]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990350] ata6.00: status: { DRDY }
[115786.990355] ata6.00: cmd 61/08:50:9f:37:b7/00:00:07:00:00/40 tag 10 ncq 4096 out
[115786.990356]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990360] ata6.00: status: { DRDY }
[115786.990365] ata6.00: cmd 61/08:58:27:7c:d1/00:00:08:00:00/40 tag 11 ncq 4096 out
[115786.990367]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990371] ata6.00: status: { DRDY }
[115786.990376] ata6.00: cmd 61/08:60:97:48:46/00:00:0d:00:00/40 tag 12 ncq 4096 out
[115786.990377]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990381] ata6.00: status: { DRDY }
[115786.990386] ata6.00: cmd 61/08:68:cf:b4:68/00:00:0e:00:00/40 tag 13 ncq 4096 out
[115786.990388]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990392] ata6.00: status: { DRDY }
[115786.990397] ata6.00: cmd 61/80:70:3f:06:94/01:00:10:00:00/40 tag 14 ncq 196608 out
[115786.990398]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990402] ata6.00: status: { DRDY }
[115786.990408] ata6.00: cmd 61/08:78:7f:a4:88/00:00:11:00:00/40 tag 15 ncq 4096 out
[115786.990409]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990413] ata6.00: status: { DRDY }
[115786.990418] ata6.00: cmd 61/08:80:37:b8:d5/00:00:13:00:00/40 tag 16 ncq 4096 out
[115786.990419]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990423] ata6.00: status: { DRDY }
[115786.990428] ata6.00: cmd 61/08:88:c7:a4:8b/00:00:1d:00:00/40 tag 17 ncq 4096 out
[115786.990430]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[115786.990454] ata6.00: status: { DRDY }
[115787.293177] ata6: soft resetting link
[115787.446158] ata6: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[115788.133592] ata6.00: configured for UDMA/133
[115788.133628] ata6: EH complete
[115787.877547] sd 5:0:0:0: [sdf] 586072368 512-byte hardware sectors (300069 MB)
[115787.877689] sd 5:0:0:0: [sdf] Write Protect is off
[115787.877692] sd 5:0:0:0: [sdf] Mode Sense: 00 3a 00 00
[115787.878746] sd 5:0:0:0: [sdf] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA

What is the true cause of this, is there anyway to get more information?

I will test soon with apic/acpi=off.

Justin.