hw.ata.ata_dma="0": can I do this during bootup at the

[Erik Hollensbe]

>>>> It would be nice if I can set hw.ata.ata_dma="0" at the loader
>>>> prompt during bootup, so that the system at least will boot from
>>>> harddisk. Is that possible?
>>> Yes, that's possible.  Drop the loader to the prompt and do the 
>>> following:
>>> set hw.ata.ata_dma=0
>>> boot
>>
>> btw: I have a similar problems, but not with the boot disc, but one of
>> my data drives, thus I want ata_dma enabled for the other discs.
>>
>> I have to dispatch a
>>
>>     atacontrol mode 1 foo UDMA33
>>
>> to set this drive (slave on second controller) to UDMA33 (otherwise it
>> would use UDMA100). But I have to do it before /etc/rc.d/fsck starts
>> accessing the device. Right now I've added above line to the beginning
>> of aforesaid script.
>> Is there a nicer/better place to tell the kernel (don't like editing 
>> the
>> rc-scripts).
>
> You can use /etc/rc.early for that. You'll have to create it if it
> doesn't yet exist. Put 'atacontrol mode 1 foo UDMA33' in it, and it
> should execute that command before mounting the drives.

Note that you can put this in loader.conf as well - if you're having 
trouble booting the system to do it, boot to "safe mode" - should get 
you in.

I have an old Aladdin V with a buggy UDMA chipset, and doing this fixed 
the problem rather nicely.

--
Erik Hollensbe <erik at hollensbe.org>