CTDP: Only do TDP down/nominal change from TNP0
Otherwise there is a flurry of TDP changes with suspend/resume
as the kernel powers devices off on suspend and brings them
back online in resume.
This also adds a mutex around the TDP operations since it is
split across two methods and can't just rely on being Serialized.
Change-Id: I7757d3ddad34ac985a9c8ce2fc202e2b2dcb2527
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/1348
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/src/northbridge/intel/sandybridge/acpi/hostbridge.asl b/src/northbridge/intel/sandybridge/acpi/hostbridge.asl
index 8dd1de6..93db98d 100644
--- a/src/northbridge/intel/sandybridge/acpi/hostbridge.asl
+++ b/src/northbridge/intel/sandybridge/acpi/hostbridge.asl
@@ -101,6 +101,8 @@
TLUD, 32,
}
+ Mutex (CTCM, 1) /* CTDP Switch Mutex (sync level 1) */
+ Name (CTCC, 0) /* CTDP Current Selection */
Name (CTCN, 0) /* CTDP Nominal Select */
Name (CTCD, 1) /* CTDP Down Select */
Name (CTCU, 2) /* CTDP Up Select */
@@ -167,11 +169,15 @@
/* Set TDP Down */
Method (STND, 0, Serialized)
{
- Store ("Set TDP Down", Debug)
-
- If (LEqual (CTCD, CTCS)) {
+ If (Acquire (CTCM, 100)) {
Return (0)
}
+ If (LEqual (CTCD, CTCC)) {
+ Release (CTCM)
+ Return (0)
+ }
+
+ Store ("Set TDP Down", Debug)
/* Set CTC */
Store (CTCD, CTCS)
@@ -189,17 +195,25 @@
/* Set PL1 */
Store (CTDD, PL1V)
+ /* Store the new TDP Down setting */
+ Store (CTCD, CTCC)
+
+ Release (CTCM)
Return (1)
}
/* Set TDP Nominal from Down */
Method (STDN, 0, Serialized)
{
- Store ("Set TDP Nominal", Debug)
-
- If (LEqual (CTCN, CTCS)) {
+ If (Acquire (CTCM, 100)) {
Return (0)
}
+ If (LEqual (CTCN, CTCC)) {
+ Release (CTCM)
+ Return (0)
+ }
+
+ Store ("Set TDP Nominal", Debug)
/* Set PL1 */
Store (CTDN, PL1V)
@@ -217,6 +231,10 @@
/* Set CTC */
Store (CTCN, CTCS)
+ /* Store the new TDP Nominal setting */
+ Store (CTCN, CTCC)
+
+ Release (CTCM)
Return (1)
}
}