• Arnd Bergmann's avatar
    [PATCH] spufs: fix mailbox polling · 3a843d7c
    Arnd Bergmann authored
    Handling mailbox interrupts was broken in multiple respects,
    the combination of which was hiding the bugs most of the time.
    
    - The ibox interrupt mask was open initially even though there
      are no waiters on a newly created SPU.
    
    - Acknowledging the mailbox interrupt did not work because
      it is level triggered and the mailbox data is never retrieved
      from inside the interrupt handler.
    
    - The interrupt handler delivered interrupts with a disabled
      mask if another interrupt is triggered for the same class
      but a different mask.
    
    - The poll function did not enable the interrupt if it had not
      been enabled, so we might run into the poll timeout if none of
      the other bugs saved us and no signal was delivered.
    
    We probably still have a similar problem with blocking
    read/write on mailbox files, but that will result in extra
    wakeup in the worst case, not in incorrect behaviour.
    Signed-off-by: default avatarArnd Bergmann <arndb@de.ibm.com>
    Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
    3a843d7c
backing_ops.c 8.07 KB