jumbled characters on serial port

Jean-Denis Boyer jdboyer at m5t.com
Sat Jun 28 02:31:24 EST 2003

> We begin getting messages on the tty, without any problem.
> We do insmod ...etc for the driver. Now during the testing some packts
> re passed (say 500.) suddenly the characters gets jumbled
> after printing

Maybe this has nothing to do with the binary data that is output.
Do you call "printk" from interrupt context?
If so, there is currently a known bug (but no fix yet) about characters
getting jumbled when using printk in interrupt context.

Look at that thread of discussion:
The subject is:
  Problem of concurrency in arch/ppc/8260_io/uart.c

As a work around, I would suggest to defer your traces to a kernel task (with schedule_task)... or to fix the bug! ;-) ...whichever is more appropriate.

 Jean-Denis Boyer, Software Designer
 M5T Centre d'Excellence en Télécom Inc.
 4283 Garlock Street
 Sherbrooke (Québec)
 (819)829-3972 x241

** Sent via the linuxppc-embedded mail list. See http://lists.linuxppc.org/

More information about the Linuxppc-embedded mailing list