Alan Cox wrote:
So, does this explain why I wouldn't have a problem at 115200 bps with
kernel 2.2.5 but why I do with 2.6.5 and 2.6.18? Both hardware and
Without a scope on the board running both 2.2 and 2.6 that would be hard
to tell.
I see. Unfortunately I don't have a scope here in my office. The modem
manufacturer does have a scope, but they only have a system running
2.6. I suppose I could have them return the test system that I sent to
them and I could reinstall it with 2.2... if you feel like that will help.
You are
making assumptions that seem unwise - eg that the code didn't happen to
work in 2.2.5 even though it was not correctly setting hardware flow
control, or that the defaults set by the user space apps run with the
distribution haven't changed and thus shown up such a problem.
Understood. Please let me know the systematic approach that you would
like me to follow in debugging this.
Also was the 2.2 and 2.6 on the same exact mainboard ?
Yes. I have several hard drives with various installations on them. I
just plug whichever drive in that I want to use for the OS version
installed. So I've got a drive with RedHat 6.0 (kernel 2.2.5) and a
separate drive with Fedora Core 2 (2.6.5). The installation that I did
for the manufacturer on a separate machine is Fedora Core 6 (2.6.18).
You've verified that flow control does not seem to be getting asserted
for h/w control on the wires
The manufacturer has verified this with their scope. I can ony do this
by watching the RTS LED on the modem... which may or may not be a
reliable way to monitor things.
Next question on the software side therefore is does the serial port have
CRTSCTS set when the problem is showing up. (stty -a </dev/ttyWhatever)
Yes. Here's what it looks like:
# stty -F /dev/ttyS1 -a
speed 115200 baud; rows 0; columns 0; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>;
eol2 = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase =
^W; lnext = ^V; flush = ^O;
min = 1; time = 0;
-parenb -parodd cs8 -hupcl -cstopb cread clocal crtscts
-ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl
-ixon -ixoff -iuclc -ixany -imaxbel
-opost -olcuc -ocrnl -onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0
bs0 vt0 ff0
-isig -icanon -iexten -echo -echoe -echok -echonl -noflsh -xcase -tostop
-echoprt -echoctl -echoke
#
Thanks,
Lee.
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