[support-gang] Real time clock battery during XO storage

[James Cameron]

On Mon, Dec 09, 2013 at 10:04:28PM -0500, Richard A. Smith wrote:
> On 12/09/2013 08:07 PM, James Cameron wrote:
> > The symptom is that pressing the power button gives about a one
> > second pulse on the power indicator, then it goes blank.  There is
> > no serial cable output from the processor.
> 
> Take a look at the EC output.  It won't be as verbose as later
> generations but might provide some clues

Thanks.  Indeed it does.  We are hitting WorkingTimeout.  The power
LED is driven for about 860 to 880ms.

!!POI!!
20111103-
Ver:1.2.1
WDT:0
BootDeepSleep
15437:SCI:01
15437:SCI:20
15437:PwrInit2
DEEP_SLEEP -> RUNNING_STATE
15559:PwrUP
15599:Seq t30
PrepSysIO
MAIN_ON disable
15604:MAIN High
15805:Seq t200
16017:SysWork
WorkingTimeout
SysPwrOff

MAIN_ON OutLOW
16730:MAIN Low
wake wlan
16755:SCI:20
-> D_S_STATE
Yawn..zzzzz


> 
> >The laptop starts fine with the RTC oscillator stopped, provided it
> >stopped because of removal of the RTC battery.  It just won't start if
> >the RTC oscillator is stopped by writing to RTC control register.
> 
> Seems to me that this is may be some sort of OFW issue.  I seem to
> remember that we store some state in the RTC memory that is checked
> at early startup.  Just stopping the OSC would leave the memory as
> is (I think).  Perhaps that confuses OFW and its waiting for the
> something to respond that never will.

I like that idea, but I'm not getting a peep out of OFW.  OFW doesn't
touch the RTC until the startup chain, which happens after serial
output begins.  (i.e. after the 'i' to interact point).

> >Speculation: the XO-1 embedded controller is not detecting a 32 KHz
> >signal from ball C8, GPIO27, or is not detecting some other normal
> >response of the processor, and is abandoning the power up.
> 
> Nope.  Not for XO-1.  Thats the SCI# signal and its an output from
> the EC (and not used). Unlike 1.5 and beyond in XO-1 there is
> minimal feedback to the EC about the state of the CPU booting.  It's
> mostly just EC timers.  I won't say its impossible but I don't have
> any memory of anything like that and a quick look at the system
> power up code doesn't bring back an memories.

Thanks, I'll have a closer look at the code.

-- 
James Cameron
http://quozl.linux.org.au/