#10964 BLOC Future : XO-1.75 A3 panel image persists after power down

[Zarro Boogs per Child]

#10964: XO-1.75 A3 panel image persists after power down
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           Reporter:  Quozl         |       Owner:  wad           
               Type:  defect        |      Status:  assigned      
           Priority:  blocker       |   Milestone:  Future Release
          Component:  hardware      |     Version:  1.75-A3       
         Resolution:                |    Keywords:  XO-1.75       
        Next_action:  add to build  |    Verified:  0             
Deployment_affected:                |   Blockedby:                
           Blocking:                |  
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Comment(by wad):

 In order to induce a clean sweep, the power to the display driver ICs
 (LCD_+1.8V)
 must persist until after the VCOM voltage decays.   With A3, the +1.8V
 rail decays
 very quickly, and pulls down LCD_+1.8V through the body diode of PQ22.

 Richard was able to fix this in software by turning off the DCON (and
 hence
 EN_LCD_PWR) 5 mS before turning off EN_MAIN_PWR.
 It will be included in the next firmware release.

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Ticket URL: <http://dev.laptop.org/ticket/10964#comment:2>
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