Re: Linux... (or anyone) and timeloss in joystick driver.

G.W. Wettstein (greg@wind.rmcc.com)
Tue, 27 Jun 1995 12:37:56 CDT


> From: Marek Michalkiewicz <marekm@i17linuxb.ists.pwr.wroc.pl>
> Date: Mon, 26 Jun 1995 17:25:10 +0200 (MET DST)
> Subject: Re: Linus... (or anyone) and timeloss in joystick driver.
>
> BTW, I have some ideas about the register dump feature. Since it is
> explicitly requested by the user, why not always print it on the console
> (like all the Oops messages) even if klogd is running? If something bad
> happened, it may be difficult to log in and kill klogd...

There is a command line option (-c) in klogd which defines the
priority level of kernel messages which are to be directed to the
console. I believe that by default anything of lower priority
(higher number) than 1 (KERN_ALERT) gets forwarded by klogd into the
syslogd facility.

You can invoke klogd with a numeric arguement to the -c switch equal
to the priority value of the messages which you would like displayed
to the console. For example to log all kernel messages of warning
priority and higher you would use: klogd -c 4

By default printk issues all its output with a priority value of
KERN_DEBUG (7). The printk's which do the register dump
(arch/i386/kernel/traps.c) use the default message priority of
KERN_DEBUG. You could run klogd with -c 7 but that would pretty much
negate the rationale for having klogd running. The other alternative
is to modify the source code in traps.c and explicitly specify that
the register dumps are to be issued with high priority levels.

I have been coding support into klogd for converting numeric kernel
addresses into symbolic values. This was prompted by some suggestions
earlier in this group that this would be a helpful feature to have.

The problem with all these issues is that when the kernel is pooping
out from underneath you there is probably no REALLY good place to
dump output.

As always,
Dr. G.W. Wettstein Oncology Research Div. Computing Facility
Roger Maris Cancer Center INTERNET: greg@wind.rmcc.com
820 4th St. N.
Fargo, ND 58122
Phone: 701-234-7556
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`The truest mark of a man's wisdom is his ability to listen to other
men expound their wisdom.' -- GWW