#12216 NORM 13.1.0: XO-1.75/XO4 don't support 1.8 volt SD cards

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Sun Nov 18 17:32:09 EST 2012

#12216: XO-1.75/XO4 don't support 1.8 volt SD cards
           Reporter:  jvonau     |       Owner:  cjb                     
               Type:  defect     |      Status:  assigned                
           Priority:  normal     |   Milestone:  13.1.0                  
          Component:  kernel     |     Version:  Software Build 12.1.0-21
         Resolution:             |    Keywords:                          
        Next_action:  never set  |    Verified:  0                       
Deployment_affected:             |   Blockedby:                          
           Blocking:             |  

Comment(by wad):

 It varies whether the SDHCI controller brings the power control pins from
 the SDHCI interface out for use externally.

 On the Via VX850 used in the XO-1.5, the SDHCI power control (both on/off
 and volt. select) was brought out to pins --- but the circuitry was flawed
 and they didn't hold their value across suspend/resume.  We fixed this
 with external circuitry but other designers might have used GPIOs instead.

 Neither of the Marvell SoCs brought the SDHCI power control signals out to
 pins, forcing the use of GPIOs instead.  Marvell's reference designs tend
 to either wire the SD cards to +3.3V, providing no control over card
 power, or wire it to their PMIC which would require an I2C command to turn
 it on/off.

Ticket URL: <http://dev.laptop.org/ticket/12216#comment:17>
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