kern/60526: Post-PAE stable SMP machine freezes

[Eugene Grosbein]

On Sun, Mar 21, 2004 at 10:51:10AM +0100, S?ren Schmidt wrote:

> >Here http://www.ussg.iu.edu/hypermail/linux/kernel/0206.1/1212.html
> >I've found the next statement:

> >>The system will lock solid when both IDE channels are accessed,
> >>and either one is using DMA. Since I want DMA, I simply abandon the
> >>secondary channel.

> >Is it possible do such a thing using FreeBSD?
> >
> >Next, Linux seem to have a workarond(?) since 2002:
> >
> >http://www.ussg.iu.edu/hypermail/linux/kernel/0206.1/0996.html
> >
> >Soren, could you please look at this?
> 
> That fix newer worked AFAIK, today linux just dont allow UDMA on the 
> ROSB4 at all.
> 
> There is no good SW fix, and its also not established that a HW fix 
> exists as well, however I cannot reproduce the problem on my ASUS 
> CUR-DLS engineering sample, but ASUS wont tell anything about it...

Ok, I've got it.

Here come two related interesting questions:

1. Is it possible to disable secondary ATA channes for FreeBSD completely?
   And have IRQ 15 free for other devices.
2. What is ata(4)'s BIOSDMA and is it possible to use it instead of PIO
   mode? I remebmer times of 2.2.x and 3.x when controller wdc used
   some kind of DMA but not UDMA.
 
Eugene Grosbein