Date: Sun, 27 Aug 1995 11:27:58 +1000 From: Bruce Evans <bde@zeta.org.au> To: bpk@kern.com, freebsd-current@freebsd.org Subject: Re: MULTIPORT flow control problems Message-ID: <199508270127.LAA24474@godzilla.zeta.org.au>
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> I'm using a 16 port BOCA multiport serial board on my FreeBSD >(950726) machine. There seems to be a bad flow control problem (drops about >50% of the characters) with any modem I put on the BOCA board. I put the >modem on com port 1, and it worked fine. I've played with stty and it >didn't seem to help at all. Flow control problems are not likely to cause that many dropped characters. Perhaps interrupts don't work right. Then the board might by accident up to about 1000 bps with 16450s and 15000 bps with 16550s. Polled mode (which you get by not putting an irq in the config) is designed to work up to these speeds. ># 16 port BOCA board >device sio2 at isa? port 0x100 tty flags 0x1001 vector siointr >device sio3 at isa? port 0x108 tty flags 0x1001 vector siointr >... Boca boards require 0x0004 in the flags. Bit 0x0004 off means that the board is AST/4 compatible. See the sio man page. I didn't know exactly what happens for Boca boards when bit 0x0004 is off. Now I do :-). Interrupts are disabled. The AST/4 uses the normal IRQ enable bit to control the compatibility mode, and the sio turns it the bit off for AST/4's to get native AST/4 mode. In -current, by default polling "by accident" is done 100 times less often, so the problem would be more obvious. Bruce
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