Il Mon, Apr 23, 2007 at 10:11:52AM +0200, Miguel Ojeda ha scritto: > On 4/22/07, Luca Tettamanti wrote: > >Probably the two siblings are enumerated only in ACPI tables. If you > >disable ACPI the kernel won't be aware of the second "core". > > > >Luca > >-- > >"Su cio` di cui non si puo` parlare e` bene tacere". > > Ludwig Wittgenstein > > > > On 4/23/07, Robert Hancock wrote: > > > >You didn't enable ACPI, it's needed for almost all systems to detect HT > >and also for many systems to detect multi-cores as well. > > > >Aside from that, in general I would say that on any modern x86 system > >ACPI should always be enabled. In many cases it seems the BIOS code is > >not tested much without ACPI anymore, so going without ACPI can be > >problematic. > > > >-- > >Robert Hancock Saskatoon, SK, Canada > >To email, remove "nospam" from hancockr@nospamshaw.ca > >Home Page: http://www.roberthancock.com/ > > > > > > Thanks all of you. It seems the problem is ACPI, however, should not > it be noted in some way? Maybe at Documentation/smp.txt, maybe at the > help section at CONFIG_SMP, maybe a "depends on ..." > > Or maybe CONFIG_SMP should enable some bits of the ACPI code needed to > detect such additional cores. "depends on" is too strong. There exists architecture without ACPI but with SMP support; even in the x86 world a number of systems still support both MPS and ACPI. Mentioning it in the help text should be enough. Roman, are you in charge for the KConfig files? --- SMP support in modern systems often relies on ACPI being active; add a couple of lines in the help text for CONFIG_SMP Signed-Off-By: Luca Tettamanti --- arch/i386/Kconfig | 3 +++ 1 file changed, 3 insertions(+) diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig index 53d6237..48ef899 100644 --- a/arch/i386/Kconfig +++ b/arch/i386/Kconfig @@ -111,6 +111,9 @@ config SMP Y to "Enhanced Real Time Clock Support", below. The "Advanced Power Management" code will be disabled if you say Y here. + Note that ACPI is often required to support newer multi-core CPUs + and HT on Intel P4 processors. + See also the , , and the SMP-HOWTO available at Luca -- "Vorrei morire ucciso dagli agi. Vorrei che di me si dicesse: ``Com'è morto?'' ``Gli è scoppiato il portafogli''" -- Marcello Marchesi