cvs commit: src/sys/dev/scc scc_core.c

[Marcel Moolenaar]

marcel      2006-07-24 22:25:16 UTC

  FreeBSD src repository

  Modified files:
    sys/dev/scc          scc_core.c 
  Log:
  If we have multiple interrupt resources, like for Z8530 clones on the
  mac-io bus, we cannot setup FAST interrupt handlers. This because we
  use spinlocks to protect the hardware and all interrupt resources are
  assigned the same interrupt handler. When the interrupt handler is
  invoked for interrupt X, it could be preempted for interrupt Y while
  it was holding the lock (where X and Y are the interrupt resources
  corresponding a single instance of this driver). This is a deadlock.
  By only using a MPSAFE handler in that case we prevent preemption.
  
  Revision  Changes    Path
  1.4       +13 -11    src/sys/dev/scc/scc_core.c