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

Zarro Boogs per Child bugtracker at laptop.org
Sun Nov 18 11:49:25 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 dsd):

 Thanks for all the input. Another question I have (happy to wait til a
 later date, don't want to further distract from bringup): is the software
 in general able to perform a complete power cycle of an external SD card,
 when using this SoC, using only the sdhci interface (no gpios, etc)? Both
 in our case, and in the normal case, if there is a difference.

 What I'm basically wondering is if the driver can safely make the
 assumption that power cycling a card is impossible unless it has a GPIO or
 platform reset method.

 In other words, is the SD card power supply routed through the SoC where
 it could potentially have an on/off switch applied at the SDHCI interface
 level, or does the SoC design effectively mandate that the power supply is
 something separate?

 Can the same response be applied to other sdhci-based systems or is the
 answer always going to be specific to the hardware implementation?

Ticket URL: <http://dev.laptop.org/ticket/12216#comment:15>
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