Date: Mon, 31 Jul 2000 11:30:00 -0500 From: "Jim King" <jim@jimking.net> To: <freebsd-alpha@freebsd.org> Subject: Serial I/O problems Message-ID: <007601bffb0c$964002e0$a44b8486@jking>
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I connected a GPS receiver to my AlphaStation 200 to use with ntpd. The receiver is connected at 9600 bps, but is not sending data constantly so the amount of data actually received by the AS200 is a lot less than 960 bytes/sec; the receiver also outputs a 1PPS signal. I've got kernel options PPS_SYNC and COM_MULTIPORT; that latter is for an STB 4Com card in an ISA slot. The 4Com is configured so all 4 ports are on IRQ 10. I modified sio.c to set the UART FIFO trigger level at 8 bytes instead of 14 bytes. (With the trigger at 14 bytes I could tons of silo overflow messages; I get an occasional one with the trigger at 8 bytes.) The problem is that after running ntpd for a while - typically between an hour and 12 hours - the AS200 locks up *tight*, no keyboard response, no ping response. It seems to lock up sooner when the GPS receiver is connected to one of the ports on the STB card, but it has also locked up using the built-in COM2. A couple times I had DDB enabled; once it looked like it was stuck in siopoll(), the other time I couldn't tell where it was (I'm pretty new to DDB). I have not tried taking out COM_MULTIPORT. Would that help? (And will I be able to find IRQ's for all four ports on the STB card?) I remember seeing some messages about high speed serial problems on the Alpha. This isn't high speed, but it's definitely problematic. Is this kind of serial I/O just a bad idea on the Alpha? fwiw I ran the GPS receiver on an x86 box for a couple days with no problem; that was using a built-in serial port and no COM_MULTIPORT. (The x86 box is unavailable so I'm not able to try the STB card in it at the moment.) Any ideas? Is this worth pursuing or would I be better off sticking the GPS recevier on an x86 box? Jim To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message
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