On Thu, 20 Dec 2007 08:16:54 -0800 "H. Peter Anvin" <[EMAIL PROTECTED]> wrote:
> Arjan van de Ven wrote: > > On Wed, 19 Dec 2007 11:48:14 -0800 > > "H. Peter Anvin" <[EMAIL PROTECTED]> wrote: > > > >> I think C3 guarantees that the cache contents stay intact, and thus > >> it might make sense in some technology to preserve the TLB as well > >> (being a kind of cache.) > > > > that sounds nice. It's fiction though ;-) > > > > The thing to realize is that linux only sees "ACPI C3"; the BIOS > > maps that C3 to.. well any of the C states the processor in the > > system has. What you're saying is afaik correct for the *hardware* > > C3, not for the "C3" that Linux sees.. > > > > Well, it can only map ACPI C3 to a state which is no more "dead" than > what would normally be permitted by C3. IIRC, C3 is allowed to > require that DMA be turned off (unlike C2), but is not allowed to > lose the CPU state. state isn't lost if the tlb or the caches are flushed... (properly, eg all pending writebacks are written back first etc) -- If you want to reach me at my work email, use [EMAIL PROTECTED] For development, discussion and tips for power savings, visit http://www.lesswatts.org -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
