Date: Wed, 29 Sep 2010 18:19:57 +0200 From: David Naylor <naylor.b.david@gmail.com> To: Andriy Gapon <avg@icyb.net.ua> Cc: Alexander Motin <mav@freebsd.org>, freebsd-current@freebsd.org Subject: Re: Safe-mode on amd64 broken Message-ID: <201009291820.02401.naylor.b.david@gmail.com> In-Reply-To: <4CA34ADC.40309@icyb.net.ua> References: <201009291207.53146.naylor.b.david@gmail.com> <201009291548.03752.naylor.b.david@gmail.com> <4CA34ADC.40309@icyb.net.ua>
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[-- Attachment #1 --] On Wednesday 29 September 2010 16:19:08 Andriy Gapon wrote: > on 29/09/2010 16:47 David Naylor said the following: > > On Wednesday 29 September 2010 15:14:08 John Baldwin wrote: > >> On Wednesday, September 29, 2010 7:37:15 am Andriy Gapon wrote: > >>> on 29/09/2010 13:40 Alexander Motin said the following: > >>>> Hi. > >>>> > >>>> David Naylor wrote: > >>>>> Trying to boot a recent (sep 23) amd64 kernel in safe-mode fails with > >>>>> ``panic: No usable event timer found!''. This occurs on two (all my) > >>>>> machines. This has been a persistent problem since the introduction > >>>>> of the event timer code. > >>>> > >>>> I've reproduced the problem. > >>>> > >>>> The reason is that all (or at least most) of devices (both PCI and > >>>> ISA), including only available in that mode i8254 and RTC timers, > >>>> failed to allocate their interrupts. While reported message is indeed > >>>> related to event timer code, problem IMHO doesn't. While without this > >>>> panic system could boot without any alive timer, I have doubts that it > >>>> would be functional without timers, USB, network and disk controllers. > >>>> > >>>> Problems seems to be the same if I am trying to boot without ACPI. > >> > >> Probably the kernel doesn't have 'device atpic' so disabling APIC > >> probably breaks all interrupts. A newer system might only describe > >> APICs via the ACPI MADT table and not provide an MP Table. In that > >> case disabling ACPI would effectively disable APIC leading to the same > >> result. > > > > Is APIC and ACPI disabled in safe-mode on amd64? > > Did you notice the code snippet below? Yes, and it managed to confuse me. > Specifically hint.acpi.0.disabled and hint.apic.0.disabled. > Don't let "arch-i386" confuse you, it means "x86" in that context. > > > This is using GENERIC, perhaps atpic should be added to the config file, > > or made mandatory for amd64 systems? > > I don't think so. Especially given that hardware might not support !APIC > case at all, even if you have atpic in your kernel. Perhaps safe-mode is no longer a viable option and should be removed from the boot menu, or renamed to "unsafe-mode"? > Alternatively, perhaps just don't use this "Safe Mode"? > What do you try to actually achieve? I was trying to boot a system and it was panicking due to stray interrupts. It turned out to be caused by HPET. I found `hint.hpet.0.clock=0' which fixed the problem. This means HPET does not work on any of my machines. The other one's symptoms are hda losing interrupts after a period of up-time. [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.15 (FreeBSD) iEYEABECAAYFAkyjZzIACgkQUaaFgP9pFrIg1ACfZw+/o3Qxa5lEAb8xUAk6NaTK w58AnAm48Je2BY2gOkrIwb8XEIAK+phn =Ogw3 -----END PGP SIGNATURE-----
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