Date: Sun, 23 Jun 1996 05:12:54 +1000 From: Bruce Evans <bde@zeta.org.au> To: FreeBSD-hackers@freebsd.org, revr@cadre.nl, wilko@yedi.iaf.nl Subject: Re: HELP: serial port grief on Asus P55TP4N Message-ID: <199606221912.FAA09329@godzilla.zeta.org.au>
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>I'm sending this to -hackers on behalf of a friend of mine who has >just converted to FreeBSD 2.1R. His system is a P100 on a Asus >P55TP4N with 32Mb, SC200 and ATI Mach64 VGA. >He has all sorts of problems when using the internal serial ports >of the Asus in combination with UUCP. It's really weird... :-( >The uucp config files are identical to mine (I have a P55TP4XE). >Symptoms: >- when X was running -> console messages 'tty level buffer overflow' >- without X -> errors logged by uucp 'uucp checksum failed' >- he also tried ijppp and that seems to work OK... (???) Uucp checksum errors are known to be caused by bugs in the UMC i/o chip which is found in some ASUS motherboards (e.g. the P55TP4XE rev.2.4). The UARTs lose sync when their speed is set while data is arriving, and uucp sets the speed a lot as a side affect of doing tcsetattr()'s (it doesn't change the speed but it I think it toggles state bit(s)). This can be worked around in most cases by changing the driver to skip setting the speed if the speed hasn't changed. Bruce
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