Re: [PATCH] 2.4.16 kernel/printk.c (per processorinitializationcheck)

[David Mosberger <davidm@hpl.hp.com>]

>>>>> On Fri, 7 Dec 2001 19:09:03 -0200 (BRST), Marcelo Tosatti <marcelo@conectiva.com.br> said:

  >> I'm not entirely sure whether this particular problem is
  >> architecture specific.  Perhaps it is and, if so, I'm certainly
  >> happy to fix it in the ia64 specific code. However, are you
  >> really 100% certain that on x86 there are no console drivers
  >> which in some fashion depend on cpu_init() having completed
  >> execution?  Note that the x86 version of cpu_init() also has
  >> printk()s.  If you're not certain of this, the AP startup problem
  >> could occur on x86, too.  I haven't looked at all the other
  >> platforms, but I suspect similar things will be true, there.

  Marcelo> Prove, please. If you show me it can also happen on other
  Marcelo> architectures, I'll be glad to apply the patch.

I'm no x86 expert, but I have the impression that
current_cpu_data.loops_per_jiffy will be invalid (probably 0) until
smp_store_cpu_info() is called in smp_callin().  If so, a console
driver using udelay() might not work properly.  I suspect there are
other issues, but this is just based on looking at the x86 source code
for 5 minutes.

	--david