<e.norum@sk.sympatico.ca> and concerns from Thomas Doerfler
<td@imd.m.ISAR.de> when he submitted the patch:
Since enabling XON/XOFF has such a major performance hit on `smart' output
devices I think it should be *off* by default. I think some thought should
be given to adding hooks for hardware that can support XON/XOFF without
software intervention, or for hardware like the 68360 SCC's that can use
large buffers, but still handle special characters immediately.
The patch you sent is a very good start, though. I just think that the
software flow control should be off -- to match the way the serial I/O
support has worked up until now.
Some lines for "documentation":
======================================
One thing should be noted: when XON/XOFF is enabled, the serial
device will always work with one-character buffers, so the interrupt
load for the CPU might get higer, especially on devices like MC68360
and MPC860, where the serial channels are capable of using big
buffers. But, once again, this only happens when XON/XOFF is actually
selected.
Please note that the flag IXON is set by default, so outgoing
XON/XOFF flow control is enabled by default.
XON/XOFF is controlled using the "standard" fields IXON/IXOFF in the
termios structure. The termios flag IXANY is not (yet) supported.
Hardware handshake for the incoming data stream is controlled using
the standard flag CRTSCTS. If this flag is set, whenever the receive
buffer is almost full, the driver function "device.stopRemoteTx()" is
called, when the receive buffer has more space available,
"device.startRemoteTx()" is called again. If the driver does not
provide these interface functions (entries in device structure are
NULL pointers), then these calls are suppressed.
Changes of the flow control options during operation should work at
any time, but this has not been extensively tested.
No changes to the device driver interface are needed.
================================================
One critical point when using this patch might be, that any BSP using
this version of termios will now have outgoing flow control enabled
by default, so the behaviour of these BSPs will change here. The
option IXON has already been set in older termios by default, but it
did not work until this patch. Maybe this option should be switched
off by default, what do you think?
joel@OARcorp.com wrote:
>
> Chris,
>
> sp09 fails on the rtems_port_delete(0) call. This is supposed to give an
> invalid id error. I can't find any changes other than the unlimited
> objects patch which would have tripped this so would appreciate it if you
> could look into it. I suspect that this is a side-effect of the unlimited
> objects patch.
>
It is me.
>
> Basically, there are 0 ports configured in sp09. The test ends up
> dereferecing NULL in local_table[0] and comes up with a non-NULL invalid
> pointer.
>
The issue is not actually allocating a local_table for an object type
which has a maximum value of 0. I cannot remember the exact workings of
the id values and the local_table. I might have changed the nature from
the pre-unlimited change. As you know the id's are an interesting game
where performance is most important.
>
> I know the problem could be solved by adding a check for index == 0. But
> I hate to slow this path down. I think you may have changed the way the
> object information structure gets initialized.
>
---- CVS log ----
This change lets the unlimited and sp09 tests run on the posix Linux
BSP. A static local variable `null_local_table' has been added. This
variable is always set to NULL. The `**local_table' element of the
information structure is set to point to this variable earily in the
initialisation. If the object type has more than 0 elements the
`local_table' element is updated. All object types which have 0 elements
reference `null_local_table'. This change fixes the problem sp09 found
yet does not add any extra processing to the critical
`_Objects_Get_local_object' function.
---- CVS log ----
There seems to be an ugly dependency between posix-headers and
libcsupport.
Configuring rtems with
../rtems-rc-19990324-0/configure \
--target=i386-rtems \
--prefix=<somewhere> \
--disable-posix
"make RTEMS_BSP=pc386" results into:
[...]
/opt/rtems/bin/i386-rtems-gcc --pipe
-B/users/rtems/src/multi/build/pc386/lib/ -specs bsp_specs -qrtems
-I/users/rtems/src/multi/build/pc386/lib/include/networking -g -Wall
-ansi -fasm -O4 -fomit-frame-pointer -c -o o-pc386/utime.o
../../../../../rtems-rc-19990324-0/c/src/lib/libc/utime.c
In file included from
../../../../../rtems-rc-19990324-0/c/src/lib/libc/utime.c:16:
/opt/rtems/i386-rtems/include/utime.h:4: sys/utime.h: No such file or
directory
../../../../../rtems-rc-19990324-0/c/src/lib/libc/utime.c:24: warning:
`struct utimbuf' declared inside parameter list
../../../../../rtems-rc-19990324-0/c/src/lib/libc/utime.c:24: warning:
its scope is only this definition or declaration,
../../../../../rtems-rc-19990324-0/c/src/lib/libc/utime.c:24: warning:
which is probably not what you want.
../../../../../rtems-rc-19990324-0/c/src/lib/libc/utime.c: In function
`utime':
../../../../../rtems-rc-19990324-0/c/src/lib/libc/utime.c:34:
dereferencing pointer to incomplete type
../../../../../rtems-rc-19990324-0/c/src/lib/libc/utime.c:34:
dereferencing pointer to incomplete type
make[4]: *** [o-pc386/utime.o] Error 1
make[3]: *** [all] Error 1
make[2]: *** [all] Error 1
make[1]: *** [all] Error 1
make[1]: Leaving directory `/lfs/poseidon/users/rtems/src/multi/build/c'
make: *** [all] Error 1
Apparently sys/utime.h is one of the posix headers and therefore gets
not installed (I suppose this is correct).
IMO, this probably indicates that sys/utime.h has to be moved to another
include subdirectory and should not be part of the posix-package.
[AFAIK, sys/*.h are system dependent headers, so why should it be a
posix-header? - Hmm]
First, the unlimited patch. I have compiled the unlmited patch for the
Linux posix BSP only and it seems to work cleanly. I would like a really
major application run on this change before commiting as the changes are
very core and significant. I am currently building all the tests to run.
I have no targets suitable to test on at the moment.
I have tested the patch for inline functions and macros.
Turning macros on has found some core bugs. I have fixed these but have
not run all the tests. Please review the patch for these changes. They
are:
1) The conditional compilation for MP support broke the core messages
code. You cannot embed a conditional macro in another macro. The Send
and Urgent Send calls are macros.
2) User extensions handler initialisation now has two parameters. I have
updated the macros to support the extra parameter.
The patch also contains the gcc-target-default.cfg fix required to build
the kernel. More of a by product than a fix for you.
would work. At the same time, the initial implementation of F_SETFL
was added. A support routine was added to convert internal libio
flags back to the POSIX style. Eventually the internal representation
should be eliminated in the interest of simplicity and code reduction.
This problem was reported by Jake Janovetz <janovetz@tempest.ece.uiuc.edu>.
> 5) rtems-rc-19990202-1.diff/reorg-install.sh
>
> reorg-install.sh fixes a Makefile variable name clash of RTEMS
> configuration files and automake/autoconf standards.
> Until now, RTEMS used $(INSTALL) for install-if-change. Automake and
> autoconf use $(INSTALL) for a bsd-compatible install. As
> install-if-change and bsd-install are not compatible, I renamed all
> references to install-if-changed to $(INSTALL_CHANGED) and used
> $(INSTALL) for bsd-install (==automake/autoconf standard). When
> automake will be introduced install-if-change will probably be replaced
> by $(INSTALL) and therefore will slowly vanish. For the moment, this
> patch fixes a very nasty problem which prevents adding any automake file
> until now (There are still more).
rather then NAME_MAX. NAME_MAX is 255 and that lets IMFS chew up memory
too fast. Perhaps in the future, the places in IMFS that put a maximum
length name string on the stack and the jnode structure does not include
a maximu length name string can be fixed so this is not a problem.
> 4) rtems-rc-19990202-0.diff /reorg-score-cpu.sh
>
> reorg-score-cpu.sh reorganizes the cpu/<cpu>/* subdirectories in a
> similar manner than previous reorg scripts did. rtems-rc-19990202-0.diff
> contains the diffs after reorg-score-cpu.sh has been run on a
> rtems-19981215 snapshot + my patches up to rtems-rc-19990131-2.diff.
>
> This patch is rather nasty and may break something. However, I've tested
> it for about 10 different target/bsp pairs and believe to have shaken
> out most bugs.
I wonder about the following .h files that were not moved:
a29k/asm.h
a29k/cpu_asm.h
i386/asm.h
i960/asm.h
m68k/asm.h
m68k/m68302.h
m68k/m68360.h
m68k/qsm.h
m68k/sim.h
mips64orion/asm.h
mips64orion/cpu_asm.h
mips64orion/mips64orion.h
no_cpu/asm.h
no_cpu/cpu_asm.h
powerpc/asm.h
powerpc/mpc860.h
sh/asm.h
sparc/asm.h
sparc/erc32.h
> 4) rtems-rc-19990202-0.diff /reorg-score-cpu.sh
>
> reorg-score-cpu.sh reorganizes the cpu/<cpu>/* subdirectories in a
> similar manner than previous reorg scripts did. rtems-rc-19990202-0.diff
> contains the diffs after reorg-score-cpu.sh has been run on a
> rtems-19981215 snapshot + my patches up to rtems-rc-19990131-2.diff.
>
> This patch is rather nasty and may break something. However, I've tested
> it for about 10 different target/bsp pairs and believe to have shaken
> out most bugs.
I wonder about the following .h files that were not moved:
a29k/asm.h
a29k/cpu_asm.h
i386/asm.h
i960/asm.h
m68k/asm.h
m68k/m68302.h
m68k/m68360.h
m68k/qsm.h
m68k/sim.h
mips64orion/asm.h
mips64orion/cpu_asm.h
mips64orion/mips64orion.h
no_cpu/asm.h
no_cpu/cpu_asm.h
powerpc/asm.h
powerpc/mpc860.h
sh/asm.h
sparc/asm.h
sparc/erc32.h
You will find enclosed a patch which contains, for Intel PC386 target :
- an Ethernet driver for DEC21140 device based boards.
- a simple cache management with paging mechanism.
allows one to trace the enqueueing and dequeueing of messages. This
can be used to insure that packets are getting to the boundary between
the network stack and the device driver.
Joel Sherrill
Jennifer Averett