IDE (hpt370) and DMA mode switching (again)...

Hello, I wrote about a week or so ago about switching DMA modes on the HPT370 controller. I've been fiddling and have found something odd. If I compile a kernel without the 'HPT370' option in the IDE/ATA config, the machine starts okay, and after turning DMA on, the drive fetches about 21.5MB/s

Lockup on IDE HPT370 when changing DMA mode.

Hi, I've got a UDMA66 drive on a HPT370 controller. Whenever I issue a command to switch to a higher DMA mode ("hdparm -X67" or "-X68") the machine locks completely - no response to Magic SysRq at all. The drive starts in udma2 upon bootup (it's a "Nikimi NIK-XL300A", not a brand I've seen befor