Those cards are supported by Linux' kernel starting from 2.3.99-pre9 for qd6580, and starting from 2.4.10 for qd6500
With some little updates, on can make it work on 2.2 kernels (mainly ide.h to be repathed)
So as to have easy drives testing, I also wrote a little module, drivers/ide/handtune.c, which allows to tell through /proc/ide/hdx/timing which timing to be hand-used. This patch must be used to let the module set the timing.
More information is available at Petr's and at the drivers' museum