#11082 NORM 1.75-fi: Linux fails to boot when OFW audio muted

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#11082: Linux fails to boot when OFW audio muted
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           Reporter:  martin.langhoff  |       Owner:  buytenh      
               Type:  defect           |      Status:  new          
           Priority:  normal           |   Milestone:  1.75-firmware
          Component:  kernel           |     Version:  1.75-B1      
         Resolution:                   |    Keywords:               
        Next_action:  diagnose         |    Verified:  0            
Deployment_affected:                   |   Blockedby:               
           Blocking:                   |  
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Changes (by Quozl):

  * next_action:  never set => diagnose


Comment:

 I've reproduced this with a special build of OpenFirmware, which sets the
 default volume to muted.  scp dev.laptop.org:~quozl/q4b05q.rom

 Yes, OpenFirmware does not play the audio if the volume is muted.  This
 decision is in the code
 [http://tracker.coreboot.org/trac/openfirmware/browser/cpu/x86/pc/olpc/sound.fth#L32
 here].

 Lennert: you won't be able to reproduce this easily with an XO-1.75 A3
 unless it has the [http://wiki.laptop.org/go/XO_1.75_A3_ECOs#RTC_Power RTC
 Power ECO] applied (#10999).  Without it, the A3 is very likely to have
 lost the volume setting over a power cycle, because it is saved in the RAM
 of the RTC chip.  You can prove that by examining the volume setting at
 the ok prompt:

 {{{
 ok get-saved-volume .d
 -50
 }}}

 A value of -50 means muted.  A value of -9 is the default.  The default is
 set if the RTC RAM is reset by power cycle.  To reproduce it before you
 get an XO-1.75 B1, use the firmware image q4b05q.rom above.

-- 
Ticket URL: <http://dev.laptop.org/ticket/11082#comment:1>
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