USB to serial bug

math mclabon at seatech.fau.edu
Thu Feb 26 12:53:02 UTC 2004


  Hello,

I've been trying to use a Bafo Technologies BF-810 USB to serial on my 
RedHat9 (20.4.20-8) box without success.
Here's a summary of what I've tried and some strange results I got

When I plug the device, usbserial and pl2303 are loaded ok. Then I 
connect a Win box with hyperterminal to the new port, and cat 
/dev/usb/ttyUSB0
First: The fist character is never received.
There is no new line (or CR, I can never remember) at the end of the 
line on the echo received on the hyperterm (whereas CR/NL are fine with 
the same config on a regular serial port).
Then, I try to send a text file through the serial link. Everything is 
received ok on the Linux side, but the echo on hyperterm is all messed up.
Then, when I do a CTRL-C on the Linux console, my computer just freezes, 
with two LEDs on the keyboard blinking. When I do a CTRL-Z instead, and 
then send a TERM signal then a KILL to cat, the process terminates 
nicely. When I just send a KILL, it freezes again.
I get the exact same result using an application that I wrote to read 
the serial port. Everything goes well until I close( ) the device. At 
that point, the computer freezes again.
When I reboot Linux, if the hyperterm is still active on the win side, a 
get a kernel panic. If I either stop the hyperterm or disconnect the 
serial link or unplug the USB to serial, Linux boots correctly.

I've read somewhere that some people getting a kernel panic with 
usbserial and pl2303 say they solved that by upgrading the kernel. So I 
upgraded to 20.4.20-30.9.
That didn't change anything. In fact, I've read that upgrades to 2.4.23 
or higher solve the bug, but I cannot find anything higher than 
20.4.20-30.9 for RH9.

Does anybody have a suggestion about what I could try ?
Otherwise, does anybody know a USB-to-serial that works fine with 
kernels 2.4.20-8 and 2.4.20-30.9 ?
I guess I could buy a serial to pcmcia, but that's much more expensive - 
and that may not work either.

Thanks in advance.
Mathieu

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