From: hedrick@dumas.rutgers.edu (Charles Hedrick) Subject: Re: FAS driver, can it be done? Date: 14 Jun 1992 19:21:38 GMT
gkm@muug.mb.ca (Greg K. Moeller) writes:
>I've heard of the FAS serial driver that supports shared IRQs and 16550s.
>Has anyone tryed to make this work under Linux, and did it work?
I believe this is the device driver I was using in the final days of
my Microport usage. The problem is that it's a Unix driver. The
interface definitions and general coding conventions for a device
driver are very different for Linux. If there are things this driver
does that you like, you can probably take the ideas and move them into
the Linux serial driver. But I doubt that you're going to end up
moving much of the actual code. However certainly the driver will
contain all the magic needed to do shared IRQ's and 16550's, so if
somebody wanted to add those features to Linux, it would be a dandy
starting point.
Microport SV/AT had serious and continuing problems with serial lines
hanging. I tried this driver in hopes of resolving those problems.
It didn't. I think my final conclusion was that there was a race
condition elsewhere in the kernel, so just changing the device driver
couldn't fix it. I finally gave up on SV/AT for that reason. My main
use of my PC is as a terminal, so if kermit and SLIP won't work
reliably, I'm better off with DOS. Now that I've played with serial
devices under both DOS and Linux, I'm beginning to wonder if I was
getting hit by the well-known tendency of the serial lines to forget
to do transmit done interrupts. Linux works around that properly.
It's possible that this driver didn't time out writes. Linux' serial
handling was never as bad as Microport's, and now seems reliable.