RE: 16850 automatic RTS/CTS

Ed Vance (EdV@macrolink.com)
Wed, 8 May 2002 09:58:54 -0700


On Wed, May 08, 2002, Guennadi Liakhovetski wrote:
>
> As of 2.5.6 there is some support in the serial driver for the
> 16850 automatic hardware handshake feature, in particular the
> automatic CTS is enabled, but not the automatic RTS. Nor are
> the hysteresis levels set. Why? I tried enabling all these
> features, it helps a good deal improving the reliability of the
> data transfer, but still, at high baud-rates (460800, 921600)
> and in the presence of user-space load data can be overwritten
> in the driver's buffer. Why isn't this checked?

Hi Guennadi,

Like so many other good ideas, this feature support is not already there
simply because nobody has submitted a patch for it, yet. (and
followed-up/lobbied with sufficient tenacity and grace)

Also, be aware that there is in progress a rewrite of the serial driver
subsystem for 2.5. See Russell King's entry in the maintainers list.

I'm only on the 2.4 side, but I would like to see a tested patch against
either 2.5 or 2.4 for fixup of 16850 support. Since you have the 16850
hardware (and I don't), please consider creating a patch to serial.c and
friends that adds this feature support and posting it for discussion to
linux-serial@vger.kernel.org. Put enough comments at the top so anyone with
the datasheet can understand your intent.

Thanks,
Ed

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Ed Vance edv@macrolink.com
Macrolink, Inc. 1500 N. Kellogg Dr Anaheim, CA 92807
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