cvs commit: src/sys/kern subr_witness.c src/sys/dev/syscons scmouse.c syscons.c syscons.h

Scott Long scottl at
Wed Sep 13 08:48:20 PDT 2006

scottl      2006-09-13 15:48:15 UTC

  FreeBSD src repository

  Modified files:
    sys/kern             subr_witness.c 
    sys/dev/syscons      scmouse.c syscons.c syscons.h 
  Introduce a spinlock for synchronizing access to the video output hardware
  in syscons.  This replaces a simple access semaphore that was assumed to be
  protected by Giant but often was not.  If two threads that were otherwise
  SMP-safe called printf at the same time, there was a high likelyhood that
  the semaphore would get corrupted and result in a permanently frozen video
  console.  This is similar to what is already done in the serial console
  Revision  Changes    Path
  1.41      +4 -4      src/sys/dev/syscons/scmouse.c
  1.446     +17 -14    src/sys/dev/syscons/syscons.c
  1.87      +17 -1     src/sys/dev/syscons/syscons.h
  1.218     +1 -0      src/sys/kern/subr_witness.c

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