Date: Mon, 3 Mar 1997 18:54:46 +1100 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, ejs@bfd.com Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: sio projects Message-ID: <199703030754.SAA19089@godzilla.zeta.org.au>
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>> There is already some support for this (for 16550s) in sio.c. It is >> disabled because it doesn't quite work. I think auto-detection works. > >I'd be surprized if the fifo's are actually disabled, as it's hard to get >unix to do better than 19.2kbaud without them. I suspect that the The 16650 detection code is disabled, so 16550 compatibility mode (if any) is used. >> >3) Throw in a flag to use the UART-driven hardware flow control methods. >> >> The hardware flow control on at least the original 16550's is reported >> to be worse that useless because it is invoked at the wrong time - at >> the same time that a fifo-trigger-level-reached interrupt is generated >> or something like that - it breaks streaming. > >Sorry, should have been more specific.. I meant for the 650/750, for which >this supposedly was fixed. Maybe set it up to ignore the flag on 550 >chips? Oops, I meant the original 16650's. 16550's don't have automatic flow control. Bruce
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