Re: [PATCH] (Longhaul 1/5) PCI: Protect bus master DMA from Longhaul by rw semaphores

Bart Hartgers
2006-06-29T12:03:23Z

Alan Cox wrote:
> Ar Mer, 2006-06-28 am 20:25 +0200, ysgrifennodd Rafał Bilski:
>> AUTOHALT, this means interrupts must be disabled except for the time tick,
>> which should be reset to >=1ms. Care must be taken to avoid other system events
>> that could interfere with this operation. A few examples are snooping, NMI,
>> INIT, SMI and FLUSH."
>
> "snooping". So we do need the cache sorting out.
>

If I understand correctly, trouble occurs when the processor tries to
snoop? Would disabling (via MSR) and flushing the caches before changing
the frequency help in that case?

Groeten,
Bart

--
Bart Hartgers - TUE Eindhoven - http://plasimo.phys.tue.nl/bart/contact/