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NuttX TODO List (Last updated September 28, 2011)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This file summarizes known NuttX bugs, limitations, inconsistencies with
standards, things that could be improved, and ideas for enhancements.
patacongo
committed
(5) Task/Scheduler (sched/)
(1) Memory Managment (mm/)
(2) USB (drivers/usbdev, drivers/usbhost)
(5) Build system / Toolchains
(2) ARM/i.MX (arch/arm/src/imx/)
(4) ARM/STM32 (arch/arm/src/stm32/)
(2) Hitachi/Renesas SH-1 (arch/sh/src/sh1)
(4) Renesas M16C/26 (arch/sh/src/m16c)
apps/
(5) Network Utilities (apps/netutils/)
(5) NuttShell (NSH) (apps/nshlib)
(5) Other Applications & Tests (apps/examples/)
o Task/Scheduler (sched/)
^^^^^^^^^^^^^^^^^^^^^^^
Description: When a tasks exits, shouldn't all of its child pthreads also be
terminated?
Status: Open
Priority: Medium, required for good emulation of process/pthread model.
Description: atexit() supports registration of only single function called on
exit(). It should support multiple functions registered by atexit()
or onexit() and these should be called in reverse order of
registration when the task exits.
Priority: Low
Description: Implement sys/mman.h and functions
Status: Open
Priority: Low
Description: Implement sys/wait.h and functions. Consider implementing wait,
waitpid, waitid. At present, a parent has no information about
child tasks.
Update: A simple but usable version of waitpid() has been included.
This version is not compliant with all specifications and can be
enabled with CONFIG_SCHED_WAITPID.
Status: Open
Priority: Low
Description: Several APIs do not set errno. Need to review all APIs.
Status: Open
Priority: Medium, required for standard compliance (but makes the
code bigger)
o On-demand paging (sched/)
^^^^^^^^^^^^^^^^^^^^^^^^^
Description: On-demand paging has recently been incorporated into the RTOS.
The design of this feature is described here:
http://www.nuttx.org/NuttXDemandPaging.html.
As of this writing, the basic feature implementation is
complete and much of the logic has been verified. The test
harness for the feature exists only for the NXP LPC3131 (see
configs/ea3131/pgnsh and locked directories). There are
some limitations of this testing so I still cannot say that
the feature is fully functional.
o Other core OS logic
^^^^^^^^^^^^^^^^^^^
Description: get_environ_ptr() (sched/sched_getenvironptr.c) is not implemented.
The representation of the the environment strings selected for
NutX is not compatible with the operation. Some significant
re-design would be required to implement this funcion and that
effort is thought to be not worth the result.
Status: Open
Priority: Low -- There is no plan to implement this.
Description: timer_getoverrun() (sched/timer_getoverrun.c) is not implemented.
Status: Open
Priority: Low -- There is no plan to implement this.
o Memory Managment (mm/)
^^^^^^^^^^^^^^^^^^^^^^
Description: Add an option to free all memory allocated by a task when the
task exits. This is probably not be worth the overhead for a
deeply embedded system.
There would be complexities with this implementation as well
because often one task allocates memory and then passes the
memory to another: The task that "owns" the memory may not
be the same as the task that allocated the memory.
Status: Open
Priority: Medium/Low, a good feature to prevent memory leaks but would
have negative impact on memory usage and code size.
o Signals (sched/, arch/)
^^^^^^^^^^^^^^^^^^^^^^^
Description: 'Standard' signals and signal actions are not supported.
(e.g., SIGINT, SIGCHLD, SIGSEGV, etc).
Status: Open
Priority: Low, required by standards but not so critical for an
embedded system.
Description: sig_notify() logic does not support SIGEV_THREAD; structure
struct sigevent does not provide required members sigev_notify_function
or sigev_notify_attributes.
Status: Low, there are alternative designs. However, these features
are required by the POSIX standard.
Priority: Low for now
o pthreads (sched/)
^^^^^^^^^^^^^^^^^
Description: pthread_cancel(): Should implement cancellation points and
pthread_testcancel()
Status: Open
Priority: Low, probably not that useful
^^^^^^^^^^^
Description: Need to call static constructors
Status: Open
Priority: Low, depends on toolchain. Call to gcc's built-in static
constructor logic will probably have to be performed by
user logic in user_start().
Description: Not all of the NXFLAT test under apps/examples/nxflat are working.
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Most simply do not compile yet. tests/mutex runs okay but
outputs garbage on completion.
Status: Open
Priority: High
Description: The ARM up_getpicbase() does not seem to work. This means
the some features like wdog's might not work in NXFLAT modules.
Status: Open
Priority: Medium-High
Description: At present, all .rodata must be put into RAM. There is a
tentative design change that might allow .rodata to be placed
in FLASH (see Documentation/NuttXNxFlat.html).
Status: Open
Priority: Medium
Description: If the function pointer to a statically defined function is
taken, then GCC generates a relocation that cannot be handled
by NXFLAT. There is a solution described in Documentataion/NuttXNxFlat.html,
by that would require a compiler change (which we want to avoid).
The simple workaround is to make such functions global in scope.
Status: Open
Priority: Low (probably will not fix)
Description: In the NXFLAT symbol tables... Using a 32-bit hash value instead
of a string to identify a symbol should result in a smaller footprint.
Status: Open
Priority: Low
Description: Windows build issue. Some of the configurations that use NXFLAT have
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