From:	"Tonu Aas" <tonu AT ids DOT ee>
Newsgroups:	comp.os.msdos.djgpp
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Subject:	Re: Libnet serial port problem
Date:	Wed, 15 Jan 2003 10:11:17 +0200
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To:	djgpp AT delorie DOT com
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> > If they use the same IRQ(COM1, COM3 or COM2 COM4) then its normal.
>
> No. Just bad software. There are enough status bits on the UART chip to
> see which one has raised the interrupt. It just slows down a little
> bite, because you have to ask all possible UART that are sharing the
> same IRQ.

You expect that UARTS can share IRQ-s.
I dont know, but on older machines they dont.
At least ISA bus IO cards dont. So its not "Just bad software" but can
be also bad harware as most PC platform hardware is.

I think that this libnet is some older library and it doesnt handle IRQ
sharing also.
Only bullet-proof solution is to not use the same IRQ or not to use IRQ at
all :[

Tõnu.

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