#10073 NORM Not Tri: OFW page fault after reboot / jump to Linux hang

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#10073: OFW page fault after reboot / jump to Linux hang
---------------------------------+------------------------------------------
 Reporter:  rsmith               |                 Owner:  wmb at firmworks.com
     Type:  defect               |                Status:  new              
 Priority:  normal               |             Milestone:  Not Triaged      
Component:  ofw - open firmware  |               Version:  not specified    
 Keywords:                       |           Next_action:  never set        
 Verified:  0                    |   Deployment_affected:                   
Blockedby:                       |              Blocking:                   
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 This is for tracking information on what started as the OFW page fault
 problem after runin bug and has now moved into a hang when loading linux.

 Quick summary:

 Various firmwares < q3a35 would page fault after reboots on some machines.
 With q3a35 the page fault seems to have disappeared but has been replaced
 by a hang while loading Linux.  This is repeatable give enough reboots and
 occurs with a serial port attached (the page fault went away when serial
 ports were attached)

 The serial log for a good boot on the test machine looks like this:

 {{{
 OLPC D3, 512 MiB memory installed, S/N SHC95000199
 OpenFirmware  CL1   Q3A35  Q3A   EC Firmware Ver:1.9.24

 Type the Esc key to interrupt automatic startup
 Boot device: /sd/disk at 3:\boot\olpc.fth  Arguments:
 Boot device: /pci/sd at c/disk at 3:\boot\vmlinuz  Arguments: rdinitdebug
 console=ttyS0,115200 console=tty0 fbcon=font:SUN12x22
 Loading ramdisk image from /pci/sd at c/disk at 3:\boot\initrd.img ...
 [    0.000000] Linux version 2.6.31_xo1.5-20100127.1842.1.olpc.ee37899
 (cjb at bob.laptop.org) (gcc version 4.4.0 20090506 (Red Hat 4.4.00
 [    0.000000] KERNEL supported cpus:
 [    0.000000]   Intel GenuineIntel
 }}}

 and the kernel loads.
 When the failure occurs we get this:
 {{{
 OLPC D3, 512 MiB memory installed, S/N SHC95000199
 OpenFirmware  CL1   Q3A35  Q3A   EC Firmware Ver:1.9.24

 Type the Esc key to interrupt automatic startup
 Boot device: /sd/disk at 3:\boot\olpc.fth  Arguments:
 Boot device: /pci/sd at c/disk at 3:\boot\vmlinuz  Arguments: rdinitdebug
 console=ttyS0,115200 console=tty0 fbcon=font:SUN12x22
 }}}

 So the initrd is somehow failing to load.

-- 
Ticket URL: <http://dev.laptop.org/ticket/10073>
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