[PATCH v2] Documentation / cpu hotplug: Rephrase the outdated description for MADT entries

From: Hanjun Guo
Date: Fri Jun 21 2013 - 05:12:12 EST


More than 256 entries in ACPI MADT is supported from ACPI 3.0, so the
information should be updated.

-v2: Rephrase the information instead of simply removing it according
to Rafael's advice.

Suggested-by: Rafael J. Wysocki <rjw@xxxxxxx>
Signed-off-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
---
Documentation/cpu-hotplug.txt | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt
index 9f40135..67f733d 100644
--- a/Documentation/cpu-hotplug.txt
+++ b/Documentation/cpu-hotplug.txt
@@ -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.

User Space Notification

--
1.7.9.5

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