Date: Thu, 05 Mar 1998 18:13:13 GMT From: jak@cetlink.net (John Kelly) To: "John S. Dyson" <toor@dyson.iquest.net> Cc: bde@zeta.org.au, freebsd-current@FreeBSD.ORG Subject: Re: silo overflows (Was Re: 3.0-RELEASE?) Message-ID: <3501e530.19324702@mail.cetlink.net> In-Reply-To: <199803051743.MAA01239@dyson.iquest.net> References: <199803051743.MAA01239@dyson.iquest.net>
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On Thu, 5 Mar 1998 12:43:39 -0500 (EST), "John S. Dyson" <toor@dyson.iquest.net> wrote: >John Kelly said: >> >> The problem is related to the 650 UART support in sio.c. The 550 >> support works fine. >> >I have tried to figure out the problems. I have written 16550 code >for the last 10yrs or so, and the 650 seems to be somehow more different >than the datasheets imply :-(. Several months ago I had a long exchange with Bruce about 650 UARTs and how to best handle them in sio.c. I wanted to poke around with the 650 support but I never found the time. Too many priorities to juggle. At first I argued that we should turn on the 650 auto RTS, but after reflecting on what he said I have to agree with him that the 650 auto RTS has little practical benefit and it should *not* be turned on. He did say that the 650 auto CTS would be helpful. But after these several months have passed I don't remember why! I might be able to dig out those old messages. I think I archived them. It might also be helpful to set the transmit FIFO trigger level higher than one to avoid transmit underruns. Setting EFR bit 4 to 1 and FCR bits 6 and 7 to 00 should select a transmit FIFO trigger level of 8. If EFR bit 4 is not set to 1, the transmit trigger level defaults to 1 just like a 550. But otherwise, the 650 code should be no different from the 550 code (aside from the larger FIFO sizes). -- Browser war over, Mozilla now free. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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