Messages in this thread | | | Date | Sun, 14 Sep 2008 17:59:29 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH] apci: dump slit |
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On Sun 2008-09-14 14:26:18, Ingo Molnar wrote: > > * Pavel Machek <pavel@suse.cz> wrote: > > > On Fri 2008-09-12 23:19:21, Thomas Gleixner wrote: > > > On Fri, 12 Sep 2008, Andi Kleen wrote: > > > > "Yinghai Lu" <yhlu.kernel@gmail.com> writes: > > > > > > > > > > to see how wrong could be set by BIOS. > > > > > > > > Just dump it from user space then. There are plenty of tools > > > > to access ACPI tables. > > > > > > 1.) what guarantees that we reach user space ? > > > > We can dump in *any* kernel. > > > > > 2) If it is _valuable_ information which we can gather via kernel > > > output, then it is much more conveniant than asking the user to type > > > whatevercryptictoolcommandline and provide the output. > > > > Ooh, 'lets dump more junk at everyone, typing commands is hard' :-(. > > no, the principle is, information like the boot-time CPUID information > (and even the BIOS environment) can be indicative of _kernel bugs_. It > is often essential to dump what the booting (and failing) kernel thinks > is its environment. > > Often that environment is corrupted (by the kernel) and that leads to > problems. This 'environment' can also be affected by things like hard > boot vs cold boot differences, whether it's in a kexec environment, > whether it's booted as a virtual guest, etc., etc. > > For a long time we had the kernel's x86 bootup pretty much as a mostly > silent black box and when it broke we tried to figure things out > afterwards which was difficult and error-prone. Now we've got various > quite effective debug mechanisms (which includes printouts as well) and > figuring out x86 problems is visibly easier. We definitely wont go back > to the 'black box code, can only be debugged by a few experts' method. > > So extending on that is a good and obvious idea in general - and i agree > with Peter that this should be command-line dependent, i.e. not printed > by default. Only printing it when 'debug' is specified on the command > line is a good solution.
Dumping when user requested it on commandline seems like good compromise to me. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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