diff options
Diffstat (limited to 'cpukit/posix/include')
-rw-r--r-- | cpukit/posix/include/rtems/posix/priority.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/cpukit/posix/include/rtems/posix/priority.h b/cpukit/posix/include/rtems/posix/priority.h index ce925b6d58..c0253f3bab 100644 --- a/cpukit/posix/include/rtems/posix/priority.h +++ b/cpukit/posix/include/rtems/posix/priority.h @@ -15,9 +15,15 @@ * "Numericallly higher values represent higher priorities." * * Thus, RTEMS Core has priorities run in the opposite sense of the POSIX API. + * + * There are only 254 posix priority levels since a task at priority level + * 255 would never run because of the RTEMS idle task. This is necessary + * because GNAT maps the lowest Ada task priority to the lowest thread + * priority. The lowest priority Ada task should get to run, so there is + * a fundamental conflict with having 255 priorities. */ -#define POSIX_SCHEDULER_MAXIMUM_PRIORITY (255) +#define POSIX_SCHEDULER_MAXIMUM_PRIORITY (254) #define POSIX_SCHEDULER_MINIMUM_PRIORITY (1) |