Problems with Promise FastTrak

After updating to 5.2-BETA when the disk on the Pormise controler is accessed,
the system stalls (>10s) frequently (~ once per 5 min) and the overall
throughput dropped to around 1-2 MB/s.

Although it's only one disk, it's accessed via /dev/ar0,
and the disk is also the Slave and there is no master.
This worked on 5.1 without any problems.


    ---->8----
ATA channel 0:
    Master:  ad0 <IC35L120AVV207-0/V24OA63A> ATA/ATAPI rev 6
    Slave:       no device present
ATA channel 1:
    Master:      no device present
    Slave:  acd0 <20X10/H.DH> ATA/ATAPI rev 0
ATA channel 2:
    Master:      no device present
    Slave:   ad5 <IC35L120AVV207-0/V24OA63A> ATA/ATAPI rev 6
ATA channel 3:
    Master:      no device present
    Slave:       no device present
    ----8<----

    ---->8----
Master = BIOSPIO
Slave  = UDMA100
    ----8<----

    ---->8----
atapci0_at_pci0:6:0:       class=0x010485 card=0x807e1043 chip=0x5275105a rev=0x01 hdr=0x00
    vendor   = 'Promise Technology Inc'
    device   = 'PDC20276 Ultra133 TX2/FastTrak TX Lite EIDE Controller'
    class    = mass storage
    subclass = RAID
    ----8<----

Andy