PROBLEM: SATA AHCI driver significant throughput loss in 2.6.22-rc5-g75154f40-dirty

[Dan <metalifloyd@gmail.com>]

Something changed with the AHCI SATA driver in the latest git version.
With 2.6.21 I get ~49MB/sec according to hdparm. Using the latest git
version I only get ~8MB/sec. I've attached my .config and have
included some info about my system below. Please let me know if you
need more information or if I can help test anything.

Lenovo Thinkpad T60p

kernel information:
===================
Linux lappy 2.6.22-rc5-g75154f40-dirty #1 SMP PREEMPT Sat Jun 23
21:14:49 EDT 2007 i686 Genuine Intel(R) CPU T2600 @ 2.16GHz
GenuineIntel GNU/Linux

Gnu C                  4.1.2
Gnu make               3.81
binutils               2.17
util-linux             2.12r
mount                  2.12r
module-init-tools      3.2.2
e2fsprogs              1.39
Linux C Library        > libc.2.5
Dynamic linker (ldd)   2.5
Procps                 3.2.7
Net-tools              1.60
Kbd                    1.12
Sh-utils               6.9
udev                   104
wireless-tools         28
Modules Loaded         fglrx agpgart af_packet snd_pcm_oss
snd_mixer_oss ipw3945 ieee80211 ieee80211_crypt snd_hda_intel snd_pcm
snd_timer snd soundcore snd_page_alloc e1000 psmouse evdev unix



hdparm -i /dev/sda
==================
/dev/sda:

Model=HTS721010G9SA00                         , FwRev=MCZIC10V,
SerialNo=      MPDZN7Y0HKTYZL
Config={ HardSect NotMFM HdSw>15uSec Fixed DTR>10Mbs }
RawCHS=16383/16/63, TrkSize=0, SectSize=0, ECCbytes=4
BuffType=DualPortCache, BuffSize=7538kB, MaxMultSect=16, MultSect=?16?
CurCHS=16383/16/63, CurSects=16514064, LBA=yes, LBAsects=195371568
IORDY=on/off, tPIO={min:120,w/IORDY:120}, tDMA={min:120,rec:120}
PIO modes:  pio0 pio1 pio2 pio3 pio4
DMA modes:  mdma0 mdma1 mdma2
UDMA modes: udma0 udma1 udma2 udma3 udma4 *udma5
AdvancedPM=yes: mode=0x80 (128) WriteCache=enabled
Drive conforms to: ATA/ATAPI-7 T13 1532D revision 1:  ATA/ATAPI-2,3,4,5,6,7

cat /proc/modules
=================
fglrx 649632 15 - Live 0xf8a90000 (P)
agpgart 30412 1 fglrx, Live 0xf894e000
af_packet 23816 2 - Live 0xf893c000
snd_pcm_oss 40736 0 - Live 0xf88eb000
snd_mixer_oss 17536 1 snd_pcm_oss, Live 0xf88b4000
ipw3945 201124 1 - Live 0xf8909000
ieee80211 33608 1 ipw3945, Live 0xf88e1000
ieee80211_crypt 8704 1 ieee80211, Live 0xf887d000
snd_hda_intel 243864 0 - Live 0xf8958000
snd_pcm 68996 2 snd_pcm_oss,snd_hda_intel, Live 0xf88f7000
snd_timer 22148 1 snd_pcm, Live 0xf8872000
snd 45412 5 snd_pcm_oss,snd_mixer_oss,snd_hda_intel,snd_pcm,snd_timer,
Live 0xf8881000
soundcore 10208 1 snd, Live 0xf885a000
snd_page_alloc 11400 2 snd_hda_intel,snd_pcm, Live 0xf884b000
e1000 118080 0 - Live 0xf8896000
psmouse 38416 0 - Live 0xf8867000
evdev 11648 0 - Live 0xf8847000
unix 29584 62 - Live 0xf8851000

Attachment: .config
Description: Binary data

Attachment: lspci-vvv
Description: Binary data

Attachment: proc-cpuinfo
Description: Binary data

Attachment: proc-iomem
Description: Binary data

Attachment: proc-ioports
Description: Binary data