cafe_ccic smbus issues

Jonathan Corbet corbet at lwn.net
Mon Apr 30 11:55:45 EDT 2007


Andres Salomon <dilinger at laptop.org> wrote:

> The question is now, why wouldn't we be seeing interrupts?

A good question.  

Anyway...possible reasons for not getting interrupts:

 - Something changed in the pre-b3 board such that the interrupt line
   from the camera controller no longer reaches the CPU.  Seems
   unlikely.

 - Something changed in the Cafe startup dance with the result that
   interrupts are no longer being enabled in the controller.  That
   ritual has changed before...have there been Cafe changes this time
   around? 

 - The interrupt line is being masked in the CPU somehow.  Are there any
   "nobody cared!" messages in the logs?  What else is sharing the
   camera interrupt line on this board?

 - This board has the faster processor, right?  It's possible that there
   is a timing-related issue somewhere - the controller needs a delay
   that wasn't required before.

jon



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