devc-ser8250 behavior

QNX Newsgroups (Archives) qdn.public.qnxrtp.os
#1

Greetings. I was playing with my “transfer the file over the serial port”
software for my embedded thingie, and I ran into something that I guess you
guys should know about. In the name of efficiency I decided to read/write 4k
packets of data. However the raw input buffer size by default is 2k, and I did
verify that creeping up on 2k sized packets did eventually choke as I got close
enough. It’s not so much that you can’t read an entire 4k packet in one
readcond() call if you only have a 2k buffer, it’s that if you try it, it
apparently locks up devc-ser8250 tight as a drum. When you’ve only got one
serial port tied to your embedded thingie, this means you have to reset the
system. If impossible requests like that are presented, shouldn’t something
complain at you or only return 2k or something instead of giving up the ghost?
Hopefully it won’t be a major deal to add something to protect us from
ourselves. :slight_smile:

-Warren “my buffer runneth over” Peece

#2

Thanks, I’ll file a bug report on this.

Previously, Warren Peece wrote in qdn.public.qnxrtp.os:

Greetings. I was playing with my “transfer the file over the serial port”
software for my embedded thingie, and I ran into something that I guess you
guys should know about. In the name of efficiency I decided to read/write 4k
packets of data. However the raw input buffer size by default is 2k, and I did
verify that creeping up on 2k sized packets did eventually choke as I got close
enough. It’s not so much that you can’t read an entire 4k packet in one
readcond() call if you only have a 2k buffer, it’s that if you try it, it
apparently locks up devc-ser8250 tight as a drum. When you’ve only got one
serial port tied to your embedded thingie, this means you have to reset the
system. If impossible requests like that are presented, shouldn’t something
complain at you or only return 2k or something instead of giving up the ghost?
Hopefully it won’t be a major deal to add something to protect us from
ourselves. > :slight_smile:

-Warren “my buffer runneth over” Peece
\

#3

Would you be willing to send me your code?

Chris Foran
cforan@qnx.com



Previously, Warren Peece wrote in qdn.public.qnxrtp.os:

Greetings. I was playing with my “transfer the file over the serial port”
software for my embedded thingie, and I ran into something that I guess you
guys should know about. In the name of efficiency I decided to read/write 4k
packets of data. However the raw input buffer size by default is 2k, and I did
verify that creeping up on 2k sized packets did eventually choke as I got close
enough. It’s not so much that you can’t read an entire 4k packet in one
readcond() call if you only have a 2k buffer, it’s that if you try it, it
apparently locks up devc-ser8250 tight as a drum. When you’ve only got one
serial port tied to your embedded thingie, this means you have to reset the
system. If impossible requests like that are presented, shouldn’t something
complain at you or only return 2k or something instead of giving up the ghost?
Hopefully it won’t be a major deal to add something to protect us from
ourselves. > :slight_smile:

-Warren “my buffer runneth over” Peece
\

#4

Certainly. It’ll have to wait until Thursday however, as I’ve got to go
meet with the County Health department tomorrow which is an all day affair
and a 4-hour drive one way :frowning:

-Warren “yes, I may have screwed it up” Peece


“Chris Foran” <cforan@qnx.com> wrote in message
news:Voyager.001219173233.1281L@funnel.qnx.com…

Would you be willing to send me your code?

Chris Foran
cforan@qnx.com



Previously, Warren Peece wrote in qdn.public.qnxrtp.os:
Greetings. I was playing with my “transfer the file over the serial
port”
software for my embedded thingie, and I ran into something that I guess
you
guys should know about. In the name of efficiency I decided to
read/write 4k
packets of data. However the raw input buffer size by default is 2k,
and I did
verify that creeping up on 2k sized packets did eventually choke as I
got close
enough. It’s not so much that you can’t read an entire 4k packet in one
readcond() call if you only have a 2k buffer, it’s that if you try it,
it
apparently locks up devc-ser8250 tight as a drum. When you’ve only got
one
serial port tied to your embedded thingie, this means you have to reset
the
system. If impossible requests like that are presented, shouldn’t
something
complain at you or only return 2k or something instead of giving up the
ghost?
Hopefully it won’t be a major deal to add something to protect us from
ourselves. > :slight_smile:

-Warren “my buffer runneth over” Peece

\