Date: Fri, 15 Feb 2008 01:09:18 +0100 From: "Julian H. Stacey" <jhs@berklix.org> To: freebsd-stable@FreeBSD.ORG Cc: Oliver Fromme <olli@lurza.secnetix.de> Subject: Re: dmesg : no output on 1 of 2 7-stable boxes Message-ID: <200802150009.m1F09IPr045943@fire.js.berklix.net> In-Reply-To: <200802061517.m16FHslq067364@lurza.secnetix.de> References: <200802061517.m16FHslq067364@lurza.secnetix.de>
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Oliver Fromme wrote: > Hello Julian, > > I'm sorry this is a late reply, but I noticed your post > on the freebsd-stable list just now. > > One of 2 laptops running 7-stable shows nothing with dmesg, (other is OK). > Did you try "dmesg -a"? Thanks Oliver, Yes, but after posting I think, (Been a while can't remember), Symptom stopped after "cd /usr/local/lib; mv wine wine.MV" (a bad port !). It was filling console buf with junk. > The dmesg buffer is a circular buffer containing both > kernel output and console output. However, "dmesg" > displays only the kernel output. If there was lots of > console output, it filled all of the dmesg buffer, > so "dmesg" displays nothing (all of the kernel output > was overwritten by console output). "dmesg -a" will > display everything, i.e. kernel + console output. Some of that description could usefuly be added to `man dmesg` ? Might some commiter wnat to hack a few words in ? Or do we neeed a formal send-pr (that a commiter would rephrase likely anyway, so best skip the send-pr ? ). > If "dmesg -a" doesn't print anything either, I'm afraid > I have no idea what might be wrong. Well, you could try > "sysctl -b kern.msgbuf" which will retrieve the raw > contents of the dmesg buffer. > > > - I tried loader.conf kern.msgbuf=64000 > > I think it must be a multiple of the pages size, i,e, > 4K = 4096 on FreeBSD/i386. I usually set it to 65536 > or 131072. Ah! Certainly plausible re. 2 base N. On 7.0PRERELEASE I see kern.msgbuf= sundry text diagnostsics so seems inappropriate to set that var to a number. I see kern.consmsgbuf_size: 8192 so tried in /boot/loader.conf kern.consmsgbuf_size=4096 but even reducing size failed to vary size (enlarging had earlier failed) Some clue in sys/kern/tty_cons.c:666 I See kern.msgbuf_clear: Clear kernel message buffer kern.msgbuf: Contents of kernel message buffer Puzzled on syntax to set size in loader.conf ? -- Julian Stacey. BSD Unix Linux Net Consultant, Munich. http://berklix.com
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