Comment 7 for bug 1166246

Here's a recap of the conditions related to this bug:

1- The bug occurs _only_ when the SD slot is in use. When the root
   filesystem is installed on a USB device the bug does not occur.

2- Even if the root fs is on USB, the bug may still occur if the SD
   slot is used e.g. to copy a filesystem image on it.

3- For the bug to occur, the A15 must be running at a sufficient high
   clock (above 800MHz) and suddenly go to idle where a whole cluster
   shutdown is applied. Such condition is tricky to reproduce in
   practice as it requires only one CPU to be highly busy which
   suddenly goes idle, presumably due to waiting after IO completion.
   This might explain why the actual block device in use might matter.

4- This bug was reproduced using a Ubuntu image at least once so this
   is not Android specific. The common factor was once again IO through
   the SD slot.

5- The following errors are sent over the top left serial port each time
   this bug occurs:
   |ERROR: CA15 power down waiting for SBWFIL2
   |ERROR: CA15 power down waiting for CACTIVE (0x02)
   |ERROR: CA15 power down waiting for PWRDNACK (0x0E)

Workaround: avoid using the SD slot entirely until ARM has a fix.

I'd suggest for the Linaro media creation tools to avoid creating
filesystem images where the SD slot is specified as the root device
in the initrd and use the USB device instead in the mean time.