From b99eee8c101787682aaedb3b3a0465c6cf346725 Mon Sep 17 00:00:00 2001 From: Andrey Chernov Date: Sun, 13 Feb 1994 00:16:23 +0000 Subject: [PATCH] Man page update from wilko@idca.tds.philips.nl --- share/man/man4/man4.i386/sio.4 | 45 ++++++++++++++++++++++------------ 1 file changed, 29 insertions(+), 16 deletions(-) diff --git a/share/man/man4/man4.i386/sio.4 b/share/man/man4/man4.i386/sio.4 index 4134fa158c..5515e6560a 100644 --- a/share/man/man4/man4.i386/sio.4 +++ b/share/man/man4/man4.i386/sio.4 @@ -34,7 +34,7 @@ .\" .\" from: @(#)dca.4 5.2 (Berkeley) 3/27/91 .\" from: com.4,v 1.1 1993/08/06 11:19:07 cgd Exp -.\" $Id: sio.4,v 1.1 1993/08/28 12:41:23 rgrimes Exp $ +.\" $Id: sio.4,v 1.2 1994/02/09 23:49:45 ache Exp $ .\" .Dd February 9, 1994 .Dt SIO 4 i386 @@ -84,10 +84,20 @@ For multiport cards the .Nm flags keyword in the kernel configuration file determines which port of your multiport card is the master device, and whether the -port is part of a multiport card. The master device is the port with -the shared interrupt register. -All ports of a multiport card report -pending interrupts using this single register. +port is part of a multiport card. The master device is the port which +has register through which all interrupts of the card are funneled. +All ports of a multiport card report pending interrupts using this +single register. +.sp +The master device is indicated +.Nm bitwise +, so all sio entries in the kernel config file that are part of a +multiport card must include the correct +.Nm flags +specification. The bitwise assignment allows multiple multiport cards to +be configured in one system. It does +.Nm not +imply that the hardware can share the same physical interrupt line! .Pp In the synopsis the .Nm flags 0x401 @@ -104,10 +114,6 @@ will be .Pp Which port is the master device depends on the card type. Consult the hardware documentation of your card. -If you are shure, that your master device fully compatible with -standard port, you can ommit -.Nm flags -field from master device description line. .Pp Serial ports controlled by the .Nm sio @@ -147,18 +153,25 @@ driver is derived from the driver and is .Ud .Sh BUGS -Data loss is not near as likely on busy systems -but they still can occur at very high baud rates on slow systems. The +Data loss is not near as likely on busy systems as they are with the +.Xr com 4 +driver but they still can occur at very high baud rates on slow systems. The use of NS16550A's helps lot to handle high baud rates. .Pp +Stay away from NS16550 (so without the trailing A). These are early +implementations of the chip with non-functional FIFO hardware. +.Pp The constants which define the locations of the various serial ports are holdovers from .Nm DOS . -As shown, hex addresses can be used instead. +As shown, hex addresses can be and for clarity probably should be used instead. .Pp As usual, you get what you pay for; cheap NS16550 clones generally don't work. .Pp -The multiport example has been successfully tested with an AST/4 card, your -mileage may vary however. -.Pp -This man page can not replace the Ultimate Doc(tm): the source. +The multiport example is based on an AST/4 card, your +mileage may vary however. Note that on the AST/4 the card's dipswitches should +.Nm not +be set to use interrupt sharing. AST/4-like interrupt sharing is only used when +.Nm multiple +AST/4 cards are installed in the same system. The sio driver does not +support more than 1 AST/4 on one IRQ. -- 2.20.1