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Re: patch - at91 serial drivers assumed realtime response for DSR routines
Laurent GONZALEZ wrote:
> > This cannot be avoided. The driver must be able to respond to any
> > single character received, because an application might want to
> > receive characters sent one by one.
>
> And that is the major point. Carefully reading the at91 manual, it is to
> notice that at91 provide a powerfull timeout mechanism, to raise an
> interrupt if the line is idle after the last receive character. Using
> this, the driver will respond to a single char under ligth load, and
> will use full buffering capability under heavy load.
>
But that would result in arbitrary delays that are visible to the
application. You would need to pick some delay value at random, or
make it a configuration parameter. I find this undesirable; it is
not the driver's business to enforce this kind of policy decision
upon the application. If it needs to transfer data at a rate that
significantly loads the CPU in order to serve its purpose (maybe in
bursts only), than it must be able to do so.
tk
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Thomas Koeller, Software Development
Basler Vision Technologies
An der Strusbek 60-62
22926 Ahrensburg
Germany
Tel +49 (4102) 463-162
Fax +49 (4102) 463-239
mailto:thomas.koeller@baslerweb.com
http://www.baslerweb.com
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