Re: [ECOS] Serial overruns

[Jesper Skov <jskov at redhat dot com>]

>>>>> "Jonathan" == Jonathan Larmour <jlarmour@redhat.com> writes:

Jonathan> 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.

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

I see.

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

Probably. For reference, it's the SH serial controllers that do it all
automagically.

Jesper