Reason for the "one dot" hang found!

Paul Fox pgf at
Thu Jun 10 18:01:34 EDT 2010

daniel wrote:
 > On 10 June 2010 18:32, Bernie Innocenti <bernie at> wrote:
 > > It's the camera controller. Hence, the other module being loaded must be
 > > cafe_ccic.
 > >
 > > Looking at the initialization of cafe_ccic, there seems to be a
 > > complicated dance of mutexes and spin locks, plus a kernel thread and a
 > > bunch of sleeps. All the ingredients for a good deadlock are present :-)
 > I doubt it is directly related to locking.
 > If (as you say) there is no crash in the logs then I suspect it is
 > related to an infinite loop within the initialization code.
 > And this all seems very familiar. Google for a thread titled
 > "cafe_ccic/ov7670 hang on boot" from the 8.2 days.
 > I suspect we never fixed that bug upstream and that same commit needs
 > to be reverted from the new kernel.

good catch, good call.  commit 8815ea29a9bcbab2a3c7fbc28987cac67c2c41d0
is a revert for 6d77444aca298b43a88086be446f943cd0442ef7, and is present
in the testing branch (i.e., XO-1 802 and earlier), but not in our
current 2.6.31 branch.

 paul fox, pgf at

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