Re: serial flow control appears broken

[Lee Howard]

Alan Cox wrote:

> As the flow control is driven by software on most 16x50 chips (there are
> a couple of exceptions) if we fail to empty the fifo fast enough then any
> flow control will be asserted too late to save the day.
>
> If you stop the application and do the following
>
> 	cat /dev/ttywhatever
> 	^Z
> 	[stopped]
>
> (so you are asking the OS to buffer data but not ever reading it)
>
> and then fire data at it does the flow control eventually occur ?

Yes it does appear to.  I told the application to simply sleep(300) at 
the appropriate moment, and I watched the application and when it began 
the sleep I ran:

 cat /dev/ttyS1
 (lots of "garbage" began spewing forth)
 ^Z
 (about 2 or 3 seconds and the RTS light goes dark)

Thanks,

Lee.

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