Multiple dcons writers

Hidetoshi Shimokawa simokawa at FreeBSD.ORG
Thu Jan 10 05:23:48 PST 2008


It is unpredictable if multiple dconschat write to dcons buffer at the same
time because there is no serialization on updating the current pointer
of input buffer.
The pointer is not on the configuration rom but on the dcons buffer.
(see dcons.h)
Since dconschat polls the pointer, multiple writers work as expected
for usual interactive use.

On Jan 8, 2008 5:55 PM, Dylan Cochran <a134qaed at gmail.com> wrote:
> I've looked in the man page, and haven't found any information
> regarding multiple writers across the bus to dcons; I'm pretty sure it
> wouldn't work, but I'm not sure of the behavior defined for that
> scenario. Would both writers write to the same address given by the
> configuration rom, and stomp on each other, leaving a mess, or would
> it be serialized by the firewire card in some way? Or would an error
> be passed up to dconschat?
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/\ Hidetoshi Shimokawa
\/  simokawa at FreeBSD.ORG


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