Date: Fri, 20 Nov 2009 06:38:44 -0600 From: Karl Denninger <karl@denninger.net> To: perryh@pluto.rain.com Cc: freebsd-stable@freebsd.org Subject: Re: V8.x-PRE2 Serious PUC problem - Heads Up! Message-ID: <4B068DD4.1010301@denninger.net> In-Reply-To: <4b064f08.QD1V6fZm4C5kf4Qb%perryh@pluto.rain.com> References: <4B054DCC.6020701@denninger.net> <200911191357.nAJDvd3X095748@lava.sentex.ca> <4B054F6D.70300@denninger.net> <4b064f08.QD1V6fZm4C5kf4Qb%perryh@pluto.rain.com>
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This is a multi-part message in MIME format. --------------010305000608030701020201 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit perryh@pluto.rain.com wrote: > Karl Denninger <karl@denninger.net> wrote: > >> ... the uart driver is BROKEN. >> >> It simply locks up on the port after some period of time, >> returning nothing. I have found no way to reset the port >> other than a reboot either ... >> > > Welcome to the distant past. I'll be interested to see what > the root cause turns out to be. > > I've seen the same symptoms on: > > * A Sun-3/50 running SunOS 4.1.1_U1, using ttyb; > > * A Sun Ultra 2 running (IIRC) Solaris 2.5, > using an Aurora multi-port S-Bus card; > > * A Sun Ultra 10, using an Aurora multi-port PCI card. > > The Suns were using Aurora drivers. I was never able to get one of > those systems' ttya or ttyb (using Sun drivers, of course) to hang > that way. I know. These sorts of problems remind me of the 90s.... and 80s.... :) I've managed to put the fire out by rolling back to 7.1, but obviously this isn't a long-term solution. I'll get back on it over the weekend and during Turkey Week - my "best guess" is that there's some sort of problem with buffering somewhere. Missed interrupts should not be a factor on a PCI interface (as was occasionally an issue with the old ISA cards) but the lack of a way to poke a port and reset it elevates something like this from highly irritating to a serious issue. Finding the problem isn't going to be easy either... -- Karl --------------010305000608030701020201--
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