Date: Thu, 10 Jan 2008 22:23:45 +0900 From: "Hidetoshi Shimokawa" <simokawa@FreeBSD.ORG> To: "Dylan Cochran" <a134qaed@gmail.com> Cc: freebsd-firewire@freebsd.org Subject: Re: Multiple dcons writers Message-ID: <626eb4530801100523v16cbe40ave11033c6074536c5@mail.gmail.com> In-Reply-To: <bdf82f800801080055v530197amc45fbef735c4d50@mail.gmail.com> References: <bdf82f800801080055v530197amc45fbef735c4d50@mail.gmail.com>
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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@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? > _______________________________________________ > freebsd-firewire@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-firewire > To unsubscribe, send any mail to "freebsd-firewire-unsubscribe@freebsd.org" > > -- /\ Hidetoshi Shimokawa \/ simokawa@FreeBSD.ORG
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