I've installed 2.6.33 from the mainline ppa https://wiki.ubuntu.com/KernelMainlineBuilds so I can have a play with ATI KMS but it seems to have solved these (and my other) issues with PATA drives on VIA chipsets. Be aware though that the latest kernel won't won't with the current fglrx binary driver.
I've installed 2.6.33 from the mainline ppa https:/ /wiki.ubuntu. com/KernelMainl ineBuilds so I can have a play with ATI KMS but it seems to have solved these (and my other) issues with PATA drives on VIA chipsets. Be aware though that the latest kernel won't won't with the current fglrx binary driver.