The undocumented register BIOS uses for saving f_CNT seems to only be mapped to I/O space while all the other HPT3xx regs are dual-mapped. Looks like another HighPoint's dirty trick. With this patch, the deadly kernel oops on the cards having the modern HighPoint BIOSes is now at last gone! MBR, Sergei Signed-off-by: Sergei Shtylyov