Re: [PARPORT] Questions with ppdev

From: Philip Blundell (
Date: Sat Mar 17 2001 - 05:51:29 EST

  • Next message: Philip Blundell: "Re: [PARPORT] Console over parallel port"

    >Yes, it does, but only if you run the process with SCHED_RR or
    >SCHED_FIFO. And this is dangerous. If the process hangs (maybe because
    >of a buggy endless loop), wo can't even kill it, because the process
    >will use up all of your CPU, and you cannot type something (unless you
    >have a shell running with SCHED_RR and a higher static priority than the
    >hanging process).

    Well, you could introduce a new scheduling policy that has the realtime
    behaviour for nanosleep but behaves like SCHED_OTHER in all other respects.
    That seems like a better solution than adding wacky stuff to ppdev.

    Or, run as SCHED_OTHER most of the time but promote yourself to SCHED_RR when
    you are actually doing port I/O. That should remove most of the risk from
    infinite loops caused by bugs.


    -- To unsubscribe, send mail to: --
    -- with the single word "unsubscribe" in the body of the message. --

    This archive was generated by hypermail 2b29 : Sat Mar 17 2001 - 06:02:01 EST