Date: Wed, 29 Sep 2010 15:47:59 +0200 From: David Naylor <naylor.b.david@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: Alexander Motin <mav@freebsd.org>, freebsd-current@freebsd.org, Andriy Gapon <avg@icyb.net.ua> Subject: Re: Safe-mode on amd64 broken Message-ID: <201009291548.03752.naylor.b.david@gmail.com> In-Reply-To: <201009290914.08513.jhb@freebsd.org> References: <201009291207.53146.naylor.b.david@gmail.com> <4CA324EB.4040500@icyb.net.ua> <201009290914.08513.jhb@freebsd.org>
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--nextPart1479662.XOgHVrXr09 Content-Type: Text/Plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable 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. > > >=20 > > > 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. > > >=20 > > > I've reproduced the problem. > > >=20 > > > 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. > > >=20 > > > Problems seems to be the same if I am trying to boot without ACPI. >=20 > 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? =20 This is using GENERIC, perhaps atpic should be added to the config file, or= made=20 mandatory for amd64 systems? =20 > > It's interesting to see what the "Safe Mode" really is: > > dup bootsafekey @ =3D if > >=20 > > s" arch-i386" environment? if > > =20 > > drop > > s" acpi_load" unsetenv > > s" 1" s" hint.acpi.0.disabled" setenv > > s" 1" s" loader.acpi_disabled_by_user" setenv > > s" 1" s" hint.apic.0.disabled" setenv > > =20 > > then > > s" 0" s" hw.ata.ata_dma" setenv > > s" 0" s" hw.ata.atapi_dma" setenv > > s" 0" s" hw.ata.wc" setenv > > s" 0" s" hw.eisa_slots" setenv > > s" 1" s" hint.kbdmux.0.disabled" setenv > > 0 boot > >=20 > > Not sure if disabling ACPI on modern hardware is a good idea. > > Even more unsure about disabling APIC. > >=20 > > Makes me wonder what this could be useful for. > > Perhaps, these are just leftovers from times were ACPI, APIC (and ATA > > DMA) were all new and unproven things. >=20 > Yes, on modern machines I think disabling ACPI and APIC is less safe > actually. --nextPart1479662.XOgHVrXr09 Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.15 (FreeBSD) iEYEABECAAYFAkyjQ5MACgkQUaaFgP9pFrKR4ACgiAEqZNi3BuJUp53ynSzVGulc 07QAn3I4Yl3Cm7VUSEz0UyVoCjGzFsG6 =0tah -----END PGP SIGNATURE----- --nextPart1479662.XOgHVrXr09--
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