proposal: set default lid state to S3, performance/economy Cx states to Cmax

[John Baldwin]

On Sunday, May 04, 2014 4:27:38 am Adrian Chadd wrote:
> Hi,
> 
> I'd like to propose flipping a few things:
> 
> * Flipping the default lid state to S3. I think ACPI suspend/resume
> seems to work well enough these days and I've not met anyone lately
> who expects the default from their laptop to be "stay awake with the
> lid shut."
> * Save chip bugs that we should add workarounds for, we should be OK
> to enter lower sleep states when idling. Flipping this may expose some
> further crazy driver, platform or timer bugs, but they again likely
> should be fixed.
> 
> what do people think?

I think the lid switch thing is premature.  Even on my X220 I use a devd
hook to enable it only when i915drm is loaded as resume doesn't work until
that is done.

I think the Cmax thing OTOH is probably more appropriate.  We have several
things place that should "mostly" DTRT for picking the correct timers to
use.  The one case I know of recently were some somewhat older systems where
the HPET wasn't reliable, but the system chose to use HPET instead of LAPIC
becuase the LAPIC was known to stop during C1E, etc.  In this case the user
just stuck with plain old C1 and forced the LAPIC timer which worked fine.
However, it is hard to identify those cases.  On modern systems I would
expect the LAPIC to work just fine, so this problem will become less and
less important as time goes on.

-- 
John Baldwin