Re: [ECOS] Serial overruns

[Jonathan Larmour <jlarmour at redhat dot com>]

Jesper Skov wrote:
> 
> >>>>> "Matt" == Matt Holgate <matt@dcs.gla.ac.uk> writes:
> 
> Matt> Jonathan Larmour <jlarmour@redhat.com> writes:
> >> Still, hardware flow control should prevent this. It looks like
> >> it's gotten broken since the PC target uses the generic 16550
> >> serial driver (assuming you are using anonymous CVS, not 1.3.1),
> >> and that supports it.
> 
> Matt> What, even though it is the FIFO in the chip that is
> Matt> overflowing? I thought the hardware flow control was activated
> Matt> by software when the buffer in the serial driver reached the
> Matt> high watermark? If this is the case, then hardware flow control
> Matt> won't help a bit...or can the UART itself active flow control?
> 
> Indeed - that's what HW flow control is about.

I don't believe so actually in general:
http://www.linuxdoc.org/HOWTO/Text-Terminal-HOWTO-10.html#ss10.8
and
http://www.uclinux.org/pub/uCsimm/archive/0524.html

I do think you came across some hardware that _did_ really do it in
hardware though which may be what you were thinking of.

Jifl
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