#12032 NORM Not Tri: XO-1.5s in critical low-battery conditions do not cleanly shutdown or restart

Zarro Boogs per Child bugtracker at laptop.org
Sun Jul 29 16:30:43 EDT 2012

#12032: XO-1.5s in critical low-battery conditions do not cleanly shutdown or
           Reporter:  greenfeld            |       Owner:  rsmith                           
               Type:  defect               |      Status:  closed                           
           Priority:  normal               |   Milestone:  Not Triaged                      
          Component:  embedded controller  |     Version:  Development build as of this date
         Resolution:  invalid              |    Keywords:                                   
        Next_action:  no action            |    Verified:  0                                
Deployment_affected:                       |   Blockedby:                                   
           Blocking:                       |  

Comment(by greenfeld):

 Replying to [comment:5 rsmith]:
 > On 1.75 we dealt with this by making the EC disable run-in discharge if
 the battery hits critical.  I should probably backport those changes into
 the 1.5 firmware.
 > So rather than a hard power off it would sit there hung and the battery
 would charge back up.
 > Would this be useful?

 For the current test scenario it probably does not matter; we have the
 serial logs, and odds are SysRq commands will not do anything.

 Perhaps I should not use the word "clean" in reference to EC land when
 dealing with "hard" OS shutdowns.  My question probably should be if the
 EC should turn off the voltage regulators, etc. before the main processor
 tries to reboot a few times.   This ultimately fails on the main CPU.

 After this happens the EC may also fail to power on the XO until all power
 is removed (resetting the EC) even with external power present.  One
 XO-1.5 in particular seems prone to this.

 If the EC is supposed to shutdown the voltage regulators before the Via
 CPU starts gasping for energy, even in runin discharge mode, then there is
 still a bug.  If the EC's critical shutdown tolerances are below the main
 CPU's tolerances and this is intentionally so, then there is not an issue.

Ticket URL: <http://dev.laptop.org/ticket/12032#comment:6>
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