|author||Hanjun Guo <email@example.com>||2013-06-21 17:09:18 +0800|
|committer||Rafael J. Wysocki <firstname.lastname@example.org>||2013-06-21 13:42:17 +0200|
Documentation / CPU hotplug: Rephrase the outdated description for MADT entries
More than 256 entries in ACPI MADT is supported from ACPI 3.0, so the information in should be Documentation/cpu-hotplug.txt updated. [rjw: Changelog] Suggested-by: Rafael J. Wysocki <email@example.com> Signed-off-by: Hanjun Guo <firstname.lastname@example.org> Signed-off-by: Rafael J. Wysocki <email@example.com>
Diffstat (limited to 'Documentation')
1 files changed, 4 insertions, 2 deletions
diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt
index 9f401350f502..67f733d6f848 100644
@@ -370,8 +370,10 @@ A: There is no clear spec defined way from ACPI that can give us that
CPUs in MADT as hotpluggable CPUS. In the case there are no disabled CPUS
we assume 1/2 the number of CPUs currently present can be hotplugged.
- Caveat: Today's ACPI MADT can only provide 256 entries since the apicid field
- in MADT is only 8 bits.
+ Caveat: ACPI MADT can only provide 256 entries in systems with only ACPI 2.0c
+ or earlier ACPI version supported, because the apicid field in MADT is only
+ 8 bits. From ACPI 3.0, this limitation was removed since the apicid field
+ was extended to 32 bits with x2APIC introduced.
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