Re: serial flow control appears broken

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Maciej W. Rozycki wrote:

On Thu, 26 Jul 2007, Lee Howard wrote:

If the application were to use TIOCM_RTS how would it know when to apply it or
not?  Is there some approach that the application could take to manage flow
control on the serial port?  What about software flow control?  Does the

Well, an application could negate RTS when it receives a character and is running out of resources for further processing of incoming data.

Smarter UARTs may be able to negate RTS themselves based on the amount of data in their receive FIFO. The threshold may be configurable.


Okay, so let's say we've got a loop around a blocking read on the modem file descriptor...

 for (;;) {
     read some data from modem
     process data from modem
     if (end-of-data detected) break;
 }

Are you suggesting that the application should be using deasserting RTS after the read and asserting it before?

I had previously thought that the control of RTS was something that the serial/tty driver was supposed to do independently based on the buffer fill. Was I wrong?

Thanks,

Lee.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux