#11311 HIGH 11.3.0: Secure boot makes Linux audio unusable on XO-1

[Zarro Boogs per Child]

#11311: Secure boot makes Linux audio unusable on XO-1
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           Reporter:  greenfeld            |       Owner:  wmb at firmworks.com
               Type:  defect               |      Status:  new              
           Priority:  high                 |   Milestone:  11.3.0           
          Component:  ofw - open firmware  |     Version:  not specified    
         Resolution:                       |    Keywords:                   
        Next_action:  diagnose             |    Verified:  0                
Deployment_affected:                       |   Blockedby:                   
           Blocking:                       |  
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Comment(by dsd):

 Removing that line does indeed work around the problem. But, like you, I'd
 prefer to fix this properly.

 I'm not having much luck here though. In both the working and failure
 case, at the point of the audio driver probe routine, the PCI_COMMAND byte
 reads 0x41. The driver does try to enable bus mastering by writing 0x45,
 however upon reading immediately after, the value is still 0x41 in both
 the success and failure case.

 I used "lspci -vvvxxx" to dump the configuration space between working and
 failure cases after booting into Linux, there is no difference in the
 output.

 Also, based on your diagnosis I was expecting to be able to reproduce the
 failure in unsecure mode with:
 {{{
 select /audio
 unmap-regs boot
 }}}

 However this booted up with working audio.

 Any further ideas? Could something else be at play?

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Ticket URL: <http://dev.laptop.org/ticket/11311#comment:6>
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