Re: acpi_idle: Very idle Core i7 machine never enters C3

From: Len Brown
Date: Tue May 25 2010 - 11:40:43 EST


> > I'm told by the hardware guys that BM_STS is _not_ always
> > a NOP, and so we're not supposed to simply ignore it on C3 --
> > though it should be extremely rare that we see it set.
> > If it is ever set, it should go on and off depending on
> > activity on some latency sensitive device, like out on the LPC.
> > It may be possible for the BIOS writer to configure the chipset
> > so that BM_STS is enabled always, presumably to accomodate
> > some latency sensitve device -- or maybe by mistake.
>
> On some hardware we've seen BM_STS be enabled approximately 50% of the
> time without any obvious cause.

Assuming it is modern hardware, please get the acpidump and lspci -vv
output from that harware to this bug report:

https://bugzilla.kernel.org/show_bug.cgi?id=15886

thanks,
-Len Brown, Intel Open Source Technology Center

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