From: Luming Yu <luyu@redhat.com>
Date: Thu, 26 Mar 2009 12:58:17 +0800
Subject: [acpi] add T-state notification support
Message-id: 49CB0B69.6070507@redhat.com
O-Subject: [RHEL 5.4 PATCH] bz487567 : Add T-state notification support
Bugzilla: 487567
RH-Acked-by: Peter Martuccelli <peterm@redhat.com>
RH-Acked-by: Prarit Bhargava <prarit@redhat.com>

Description of problem:

Currently RHEL 5.x does not have T-state notification support and there is a
separate regression bug for P-state notification support.

T-state (TPC/TSS/PTC) support was put into the 2.6.23 kernel.

OSPM driver is not handling correctly two ACPI notifications from Processor
Device objects: Performance Present Capabilities Changed (0x80) and Throttling
Present Capabilities Changed (0x82). According to ACPI 3.0b after receiving the
0x80 notification, OSPM driver must get the new number of P-states by executing
_PPC object and must change the current P-state accordingly. Similarly when
0x82 notification is generated by the platform, OSPM driver must get the new
number of T-states by executing _TPC object and must change the current T-state
accordingly.

Testing status:
We are doing testing at Intel, but so far initial test results have been
very promising.

Brew info:
http://brewweb.devel.redhat.com/brew/taskinfo?taskID=1739017

Please review, test, and ACK.

Thanks,
Luming

diff --git a/drivers/acpi/processor_core.c b/drivers/acpi/processor_core.c
index 6b206e2..85ec262 100644
--- a/drivers/acpi/processor_core.c
+++ b/drivers/acpi/processor_core.c
@@ -67,6 +67,7 @@
 #define ACPI_PROCESSOR_FILE_LIMIT	"limit"
 #define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
 #define ACPI_PROCESSOR_NOTIFY_POWER	0x81
+#define ACPI_PROCESSOR_NOTIFY_THROTTLING	0x82
 
 #define ACPI_PROCESSOR_LIMIT_USER	0
 #define ACPI_PROCESSOR_LIMIT_THERMAL	1
@@ -595,6 +596,9 @@ static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
 		acpi_processor_cst_has_changed(pr);
 		acpi_bus_generate_event(device, event, 0);
 		break;
+	case ACPI_PROCESSOR_NOTIFY_THROTTLING:
+		acpi_processor_tstate_has_changed(pr);
+		acpi_bus_generate_event(device, event, 0);
 	default:
 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 				  "Unsupported event [0x%x]\n", event));
diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index db4bfd9..7c219b6 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -289,6 +289,7 @@ static inline int acpi_processor_ppc_has_changed(struct acpi_processor *pr)
 #endif				/* CONFIG_CPU_FREQ */
 
 /* in processor_throttling.c */
+int acpi_processor_tstate_has_changed(struct acpi_processor *pr);
 int acpi_processor_get_throttling_info(struct acpi_processor *pr);
 int acpi_processor_set_throttling(struct acpi_processor *pr, int state);
 extern struct file_operations acpi_processor_throttling_fops;