Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6

[pandora-kernel.git] / Documentation / cputopology.txt

diff --git a/Documentation/cputopology.txt b/Documentation/cputopology.txt
index ff280e2..bd699da 100644 (file)
--- a/Documentation/cputopology.txt
+++ b/Documentation/cputopology.txt
@@ -1,5 +1,5 @@
 
-Export cpu topology info by sysfs. Items (attributes) are similar
+Export cpu topology info via sysfs. Items (attributes) are similar
 to /proc/cpuinfo.
 
 1) /sys/devices/system/cpu/cpuX/topology/physical_package_id:
@@ -12,11 +12,10 @@ represent the thread siblings to cpu X in the same core;
 represent the thread siblings to cpu X in the same physical package;
 
 To implement it in an architecture-neutral way, a new source file,
-driver/base/topology.c, is to export the 5 attributes.
+drivers/base/topology.c, is to export the 4 attributes.
 
-If one architecture wants to support this feature, it just needs to
-implement 4 defines, typically in file include/asm-XXX/topology.h.
-The 4 defines are:
+For an architecture to support this feature, it must define some of
+these macros in include/asm-XXX/topology.h:
 #define topology_physical_package_id(cpu)
 #define topology_core_id(cpu)
 #define topology_thread_siblings(cpu)
@@ -25,17 +24,10 @@ The 4 defines are:
 The type of **_id is int.
 The type of siblings is cpumask_t.
 
-To be consistent on all architectures, the 4 attributes should have
-deafult values if their values are unavailable. Below is the rule.
-1) physical_package_id: If cpu has no physical package id, -1 is the
-default value.
-2) core_id: If cpu doesn't support multi-core, its core id is 0.
-3) thread_siblings: Just include itself, if the cpu doesn't support
-HT/multi-thread.
-4) core_siblings: Just include itself, if the cpu doesn't support
-multi-core and HT/Multi-thread.
-
-So be careful when declaring the 4 defines in include/asm-XXX/topology.h.
-
-If an attribute isn't defined on an architecture, it won't be exported.
-
+To be consistent on all architectures, include/linux/topology.h
+provides default definitions for any of the above macros that are
+not defined by include/asm-XXX/topology.h:
+1) physical_package_id: -1
+2) core_id: 0
+3) thread_siblings: just the given CPU
+4) core_siblings: just the given CPU