From owner-freebsd-hackers Sun Mar 2 23:57:25 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id XAA09194 for hackers-outgoing; Sun, 2 Mar 1997 23:57:25 -0800 (PST) Received: from godzilla.zeta.org.au (godzilla.zeta.org.au [203.2.228.19]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id XAA09173 for ; Sun, 2 Mar 1997 23:57:19 -0800 (PST) Received: (from bde@localhost) by godzilla.zeta.org.au (8.8.3/8.6.9) id SAA19089; Mon, 3 Mar 1997 18:54:46 +1100 Date: Mon, 3 Mar 1997 18:54:46 +1100 From: Bruce Evans Message-Id: <199703030754.SAA19089@godzilla.zeta.org.au> To: bde@zeta.org.au, ejs@bfd.com Subject: Re: sio projects Cc: freebsd-hackers@FreeBSD.ORG Sender: owner-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk >> 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