#11085 BLOC 1.5-har: XO-1.75 Memory errors

Zarro Boogs per Child bugtracker at laptop.org
Thu Sep 1 23:43:10 EDT 2011


#11085: XO-1.75 Memory errors
-------------------------------------------+--------------------------------
           Reporter:  wad                  |       Owner:  wad            
               Type:  defect               |      Status:  assigned       
           Priority:  blocker              |   Milestone:  1.5-hardware-C 
          Component:  ofw - open firmware  |     Version:  1.75-B1        
         Resolution:                       |    Keywords:  XO-1.75, memory
        Next_action:  reproduce            |    Verified:  0              
Deployment_affected:                       |   Blockedby:                 
           Blocking:                       |  
-------------------------------------------+--------------------------------

Comment(by wad):

 Q4B07re restored the default DQ/Addr drive settings to those use before
 Q4B05, and also changed the default PHY_RFIFO_PTR_DLY_VAL and DQ_EXT_DLY
 to 3/3.   These had been 4/4 since Q4B05.

 After a 48 hour run on 30+ laptops (additional laptops ran for less than
 48 hrs), three seg faults were seen.  Two (on laptops which had seen
 memory errors in other close to stable configurations) generated no log
 entries, other than memtester stopping due to segfault.   The third
 generated a strange error message (#11204), but also stopped memtester due
 to a seg fault.

 Playing around with other values of PHY_RFIFO_PTR_DLY_VAL and DQ_EXT_DLY
 resulted in the following observation:  No values lower than 3/3 work.
 3/2 fails, as does 3/1, 2/2, etc.  5/5 seems to work fine, and will be
 tested further.

-- 
Ticket URL: <http://dev.laptop.org/ticket/11085#comment:15>
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