Hi everyone,
                  i have the same problem with the symptoms described by CarloBecchi, also with ubuntu 9.04 with the kernel 2.6.28
My laptop is a Sony Vaio VGN A517B, with a controller

00:1f.2 IDE interface: Intel Corporation 82801FBM (ICH6M) SATA Controller (rev 03)

and a Hitachi SATA disk HTS541080G9SA00

During the use, copying moving files, the disk often freezes, and becomes more slow passing from UDMA5 to UDMA2.

At the beginning these are the conditions:

teo@vaioteo:~$ sudo hdparm -tT /dev/sda

/dev/sda:

 Timing cached reads:   1718 MB in  2.00 seconds = 859.50 MB/sec
 Timing buffered disk reads:  104 MB in  3.03 seconds =  34.30 MB/sec

teo@vaioteo:~$ sudo hdparm -v -i /dev/sda

/dev/sda:
 IO_support    =  0 (default) 
 readonly      =  0 (off)
 readahead     = 256 (on)
 geometry      = 9729/255/63, sectors = 156301488, start = 0

 Model=HTS541080G9SA00                         , FwRev=MB4OC60D, SerialNo=      MPBDL0X6GXHU8M
 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=156301488
 IORDY=on/off, tPIO={min:240,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=0xFE (254) WriteCache=enabled
 Drive conforms to: ATA/ATAPI-7 T13 1532D revision 1:  ATA/ATAPI-2,3,4,5,6,7

 * signifies the current active mode



After some use and getting worst:



teo@vaioteo:~$ sudo hdparm -tT /dev/sda

/dev/sda:
 Timing cached reads:   1566 MB in  2.00 seconds = 783.28 MB/sec
 Timing buffered disk reads:   88 MB in  3.03 seconds =  29.01 MB/sec

teo@vaioteo:~$ sudo hdparm -v -i /dev/sda

/dev/sda:
 IO_support    =  0 (default) 
 readonly      =  0 (off)
 readahead     = 256 (on)
 geometry      = 9729/255/63, sectors = 156301488, start = 0

 Model=HTS541080G9SA00                         , FwRev=MB4OC60D, SerialNo=      MPBDL0X6GXHU8M
 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=156301488
 IORDY=on/off, tPIO={min:240,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=0xFE (254) WriteCache=enabled
 Drive conforms to: ATA/ATAPI-7 T13 1532D revision 1:  ATA/ATAPI-2,3,4,5,6,7

 * signifies the current active mode

The messages in the log folder show this very quickly degradation:

Apr 27 11:05:57 vaioteo kernel: [  357.882808] ata1.00: configured for UDMA/100
Apr 27 11:07:33 vaioteo kernel: [  453.770810] ata1.00: configured for UDMA/100
Apr 27 11:15:28 vaioteo kernel: [  928.770809] ata1.00: configured for UDMA/100
Apr 27 11:16:28 vaioteo kernel: [  989.770818] ata1.00: configured for UDMA/100
Apr 27 11:17:00 vaioteo kernel: [ 1021.000054] ata1.00: limiting speed to UDMA/66:PIO4
Apr 27 11:17:00 vaioteo kernel: [ 1021.770811] ata1.00: configured for UDMA/66
Apr 27 11:21:04 vaioteo kernel: [ 1265.770814] ata1.00: configured for UDMA/66
Apr 27 11:23:24 vaioteo kernel: [ 1405.714819] ata1.00: configured for UDMA/66
Apr 27 11:25:38 vaioteo kernel: [ 1538.658829] ata1.00: configured for UDMA/66
Apr 27 11:26:40 vaioteo kernel: [ 1601.000060] ata1.00: limiting speed to UDMA/33:PIO4
Apr 27 11:26:41 vaioteo kernel: [ 1601.770824] ata1.00: configured for UDMA/33
Apr 27 11:29:16 vaioteo kernel: [ 1756.714819] ata1.00: configured for UDMA/33


The last Ubuntu distribution, without problems for me, was 7.10 with his kernel. One month ago i tried to install Lenny but the installation stopped due to the long time of copying the system to the disk. Also the installation of 9.04 was one hour long.

A similar bug effect is the

http://ubuntuforums.org/showthread.php?t=991254

I hope that someone will resolve this bug that seems to be "historical"



More detailed informations
lshw

       *-ide:1
             description: IDE interface
             product: 82801FBM (ICH6M) SATA Controller
             vendor: Intel Corporation
             physical id: 1f.2
             bus info: pci@0000:00:1f.2
             logical name: scsi0
             version: 03
             width: 32 bits
             clock: 66MHz
             capabilities: ide pm bus_master cap_list emulated
             configuration: driver=ahci latency=0 module=ahci
           *-disk
                description: ATA Disk
                product: HTS541080G9SA00
                vendor: Hitachi
                physical id: 0.0.0
                bus info: scsi@0:0.0.0
                logical name: /dev/sda
                version: MB4O
                serial: MPBDL0X6GXHU8M
                size: 74GiB (80GB)
                capabilities: partitioned partitioned:dos
                configuration: ansiversion=5 signature=6d108dc9