#12925 HIGH Future : hang on boot, circle of dots

[Zarro Boogs per Child]

#12925: hang on boot, circle of dots
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            Reporter:  Quozl   |          Owner:
                Type:  defect  |         Status:  new
            Priority:  high    |      Milestone:  Future Release
           Component:  kernel  |        Version:  Software Build 13.2.6-18
          Resolution:          |       Keywords:
          Blocked By:          |       Blocking:
Deployments affected:          |  Action Needed:  add to build
            Verified:  0       |
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Changes (by Quozl):

 * priority:  normal => high
 * next_action:  never set => add to build
 * version:  not specified => Software Build 13.2.6-18
 * milestone:  Not Triaged => Future Release


Comment:

 Camera was parasite powered through the reset signal between firmware
 startup and Linux startup, leading to crash of the SoC or an interrupt
 storm when camera controller clocks were enabled.  Unlikely to occur with
 single-core operation.

 Fix is to turn off the camera fully after firmware has identified model:
  * firmware patch
 http://dev.laptop.org/git/users/quozl/openfirmware/commit/?id=59d3e97483dcdaad1073a76438ee22e5ab0fb947
  * firmware build http://wiki.laptop.org/go/OLPC_Firmware_q7c06

 Additional fix is to detect bad firmware in kernel and allow camera to
 power down:
  * kernel patch http://dev.laptop.org/git/olpc-
 kernel/commit/?h=arm-3.5&id=34b63daf92c011f94fa54fded7c9f4847d956101
  * kernel build
 http://rpmdropbox.laptop.org/f20-xo4/kernel-3.5.7_xo4-20160113.0616.olpc.df0031f.armv7hl.rpm

 Root cause was inadequate boot testing of siv121c camera (#12785) in
 combination with dual-core feature (#12297); no production machines with
 the camera were available at the time.

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Ticket URL: <http://dev.laptop.org/ticket/12925#comment:1>
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