Date: Sat, 2 Sep 2000 08:09:00 +1000 (EST) From: Ian Smith <smithi@nimnet.asn.au> To: Warner Losh <imp@village.org> Cc: Gary Kline <kline@thought.org>, freebsd-stable@FreeBSD.ORG Subject: Re: bad 16550A maybe? Message-ID: <Pine.BSF.3.96.1000902074531.8872A-100000@gaia.nimnet.asn.au> In-Reply-To: <200009011832.MAA37168@harmony.village.org>
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On Fri, 1 Sep 2000, Warner Losh wrote: > In message <200009010501.WAA54972@tao.thought.org> Gary Kline writes: > : This just showed up on my console (and dmesg) from my new 4.1 system: > : sio0: 1 more silo overflow (total 1) > : Could this be why moused is having trouble with recognizing my > : COM1 mouse? Bad 16550A? > > Maybe. silo overflows happen because the machine is too slow to > service the interrupt before the buffer overflows (but unless it is a > 386SX25 you should have enough CPU power). It can also be caused by > baud rate mismatches, but that's fairly rare and unusual (you usually > get framing errors from a 16550A in this case). This can also be > caused by other hardware misbehaving and blocking interrupts. Regarding later messages on this also: I ran a 386SX16 under DOS 5 / DESQView (~10 tasks in 6Mb) using David Nugent's BNU FOSSIL driver as a Fidonet mailer/BBS for almost 9 years, hardly ever seeing 16550A overflows at 14 byte thresholds, albeit 14.4k. Unless a slower FreeBSD system is running with extraordinarily high interrupt latencies, it seems to me that setting a _default_ 8 byte threshold would do little more than nearly double sio interrupt frequency needlessly - even on a 386SX25! A knob, ok, sure ,, Cheers, Ian To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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