Re: serial flow control appears broken

[Lee Howard <faxguy@howardsilvan.com>]

Tilman Schmidt wrote:

> Lee Howard schrieb:
>  
>
> > 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 
> > software flow control work fine with 2.2.5 (meaning I don't see any 
> > error message and I don't have any data corruption), but neither works 
> > to avoid the "kernel: ttyS1: 1 input overrun(s)" and consequent data 
> > corruption issue in 2.6.5 nor 2.6.18.
> >
> > Was there some associated application change in tty handling that needed 
> > to occur between the 2.2 and 2.6 kernels to properly implement flow control?
> >    
>
> Could this be related?
>
> http://lkml.org/lkml/2007/7/18/245
>
> Quote:
> "I've recently found (using 2.6.21.4) that configuring a serial ports
> (ST16654) which use the 8250 driver using setserial results in the
> UART's FIFOs being disabled (unless you specify autoconfig)."
>  

I'm not running setserial on the port, myself.  But to test to see if it 
is related, I included this code in the application:

#include <linux/serial.h>
....
struct serial_struct serial;
ioctl(modemFd, TIOCGSERIAL, &serial);
traceModemOp("modem xmit_fifo_size: %u", serial.xmit_fifo_size);

And I get this resulting logging:

"MODEM modem xmit_fifo_size: 16"

So it's clear from here that the xmit_fifo_size is set correctly on this 
system.

Thanks,

Lee.

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