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authorNaga Chumbalkar <nagananda.chumbalkar@hp.com>2009-12-17 20:18:27 +0000
committerDave Jones <davej@redhat.com>2010-01-13 10:55:16 -0500
commit0f1d683fb35d6c6f49ef696c95757f3970682a0e (patch)
tree098c4510540881debdd6113e62be00f8b503ce8f /drivers/acpi
parent1dbf58881f307e21a3df4b990a5bea401360d02e (diff)
[CPUFREQ] Processor Clocking Control interface driver
Processor Clocking Control (PCC) is an interface between the BIOS and OSPM. Based on the server workload, OSPM can request what frequency it expects from a logical CPU, and the BIOS will achieve that frequency transparently. This patch introduces driver support for PCC. OSPM uses the PCC driver to communicate with the BIOS via the PCC interface. There is a Documentation file that provides a link to the PCC Specification, and also provides a summary of the PCC interface. Currently, certain HP ProLiant platforms implement the PCC interface. However, any platform whose BIOS implements the PCC Specification, can utilize this driver. V2 --> V1 changes (based on Dominik's suggestions): - Removed the dependency on CPU_FREQ_TABLE - "cpufreq_stats" will no longer PANIC. Actually, it will not load anymore because it is not applicable. - Removed the sanity check for target frequency in the ->target routine. NOTE: A patch to sanitize the target frequency requested by "ondemand" is needed to ensure that the target freq < policy->min. Can this driver be queued up for the 2.6.33 tree? Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com> Signed-off-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Dave Jones <davej@redhat.com>
Diffstat (limited to 'drivers/acpi')
-rw-r--r--drivers/acpi/processor_core.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index 41731236f9a..7fe413cc7d9 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -123,6 +123,8 @@ static const struct file_operations acpi_processor_info_fops = {
#endif
DEFINE_PER_CPU(struct acpi_processor *, processors);
+EXPORT_PER_CPU_SYMBOL(processors);
+
struct acpi_processor_errata errata __read_mostly;
static int set_no_mwait(const struct dmi_system_id *id)
{