Re: alpha iommu fixes

[Ivan Kokshaysky]

On Sat, May 19, 2001 at 06:11:27PM -0700, Richard Henderson wrote:
> I'd rather keep this around.  It should be possible to use on CIA2.

Ok. What do you think about reorg like this:
basically leave the old code as is, and add
        if (is_pyxis)
                alpha_mv.mv_pci_tbi = cia_pci_tbi_try2;
        else
                tbia test
                ...

> Uggg.  How did you discover this?

21174 docs confirm that (though in a very low voice ;-) :
 "The 21174 may hang with TBIA=3."
It hangs with TBIA=2 as well. I was able to reproduce it reliably
on sx164 with direct windows disabled just by copying 10-20 Mb via 3c905b
card -- this driver allocates/frees pci buffers at a very high
rate, so "tbia" occurs pretty often.
The fix itself took 2 days of hacking and 50+ reboots...

> Just delete it, don't comment it out.  You might mention in the
> function header comment that we're called with interrupts disabled.

Ok.

> > -	*(vip)CIA_IOC_CIA_CTRL;
> > -	mb();
> 
> I'm pretty sure you don't want to do this.

Right... I noticed these deleted lines only after posting the patch.

Ivan.