lid wakeups

Paul Fox pgf at
Tue Jun 23 11:52:40 EDT 2009

smith wrote:
 > Paul Fox wrote:
 > > but what thinking about this has really made me realize is that i
 > > don't fully understand how lid wakeups work, even for the
 > > lid-open case that we do support.  it seems that EC involvement
 > > is required, even though it's clear from the code in olpc-pm.c
 > > (and the history in #5703) that the geode gpio connections are
 > > key to the process.  are there cases where the geode isn't awake
 > > enough to force a wakeup by itself?
 > > 
 > > (i'm talking exclusively about gen1 here, btw.)
 > The  EC is involved because the EC controls the DCON power, its just not 
 > in charge.  You have to drop power to the DCON because the DCON's "low 
 > power" mode does not save you much.  So the kernel tells the EC to turn 
 > the DCON on or off.
 > On a B1 the lid signal was connected to both the geode and the EC but 
 > when we moved things around in later revs it ended up only run to the 
 > geode. (We needed EC IO)  The geode lid events turned out to be 
 > unreliable (for a never fully understood reason) and we ended up with 
 > the logic that ohm does now.

thank you.  i was misled by the EC code that still looks at the
(now-disconnected) lid signal, and by the (now-depopulated) connection
to that gpio.

 > in Gen 1.5 we expect the gpio wakeups to work correctly (which is 
 > someting we need to test soon) and lid wakeups won't be so messy.


 paul fox, pgf at

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