Problem of concurrency in arch/ppc/8260_io/uart.c

[Jean-Denis Boyer]

> Oh, I almost forgot. Yes I would like to see your test 
> program. One of the
> reasons I haven't chased the problem is because it keeps 
> disappearing;-)
> 
> Dean Dayton

Here is, in attachement, the test program.
There are two files in the tar:

  -- testprintk.c --
    A module that adds a device /dev/tpk.
    Once a file descriptor is obtained on this device,
    an internal timer starts, which calls "printk",
    each 10 ticks (100ms in my setup). When the file descriptor
    is released, the timer stops.

  -- main.c --
    A simple user mode program that opens /dev/tpk,
    and then performs an infinite loop printing to the stdout.
    When the program stops (Ctrl-C), the descriptor will be
    released by Linux, stopping the internal timer.

With that test, the problem almost immediatly appears.

BTW, the same problem is on the 860 also, which can be diagnosed the same way.

Regards,
--------------------------------------------
 Jean-Denis Boyer, B.Eng., Technical Leader
 Mediatrix Telecom Inc.
 4229 Garlock Street
 Sherbrooke (Québec)
 J1L 2C8  CANADA
 (819)829-8749 x241
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