impossible to set pata dma mode?

[Norbert Koch]

Hello.

I have to reduce dma mode from udma to wdma2
for a flash device.

In the past this was easy using atacontrol
but, afaiks it seems to be impossible using camcontrol.

 camcontrol negotiate ada0 -M wdma
...You can only modify user parameters

 camcontrol negotiate ada0 -NM wdma
Works, but I see no way how those user
parameters become active parameters as the
driver only reads then in attach as far as
I can see.

It seems like the ata driver's interface
allows to change the current settings
(XPT_SET_TRAN_SETTINGS/CTS_TYPE_CURRENT_SETTINGS)
so, why is camcontrol so restrictive?

Thank you,
Norbert Koch