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authorArthur Heymans <arthur@aheymans.xyz>2016-10-06 12:14:14 +0200
committerMartin Roth <martinroth@google.com>2016-10-09 21:37:50 +0200
commitaacd548c26f251583f1035d4ecc544198721f937 (patch)
tree0b27dc4487e846b6b6568f402cefd6963e478592
parente7aeb2f60212077521f7d71a4f485c8f4a26f6c6 (diff)
cpu/intel/model_6ex: Set msr bits for dynamic L2, C2E, C4E
The datasheets "Intel® Core™ Duo Processor and Intel® Core™ Solo Processor on 65 nm Process" mentions cpu C-states substates which can either be attained by adding a substate hint to the MWAIT/P_LVLx request or automatically by setting some msr bits correctly. This just sets the same msr bits as model_6fx to enable dynamic L2 cache, C2E and C4E acpi cpu states. The result is that when limiting a thinkpad x60 with a yonah T2400 cpu to the acpi cpu C2 state, the idle power usage drops from 18W to 14W. When the lowest C-state is set to C4 the idle power usage seems to remain similar. Change-Id: I6c422656ace04659f32082a5944617eda6c79ec3 Signed-off-by: Arthur Heymans <arthur@aheymans.xyz> Reviewed-on: https://review.coreboot.org/16901 Tested-by: build bot (Jenkins) Reviewed-by: Martin Roth <martinroth@google.com>
-rw-r--r--src/cpu/intel/model_6ex/model_6ex_init.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/src/cpu/intel/model_6ex/model_6ex_init.c b/src/cpu/intel/model_6ex/model_6ex_init.c
index 91633ecd9d..d42ff694ee 100644
--- a/src/cpu/intel/model_6ex/model_6ex_init.c
+++ b/src/cpu/intel/model_6ex/model_6ex_init.c
@@ -69,7 +69,7 @@ static void configure_c_states(void)
msr.lo |= (1 << 15); // config lock until next reset.
msr.lo |= (1 << 10); // Enable I/O MWAIT redirection for C-States
msr.lo &= ~(1 << 9); // Issue a single stop grant cycle upon stpclk
- // TODO Do we want Deep C4 and Dynamic L2 shrinking?
+ msr.lo |= (1 << 3); //dynamic L2
/* Number of supported C-States */
msr.lo &= ~7;
@@ -103,7 +103,13 @@ static void configure_misc(void)
// TODO: Only if IA32_PLATFORM_ID[17] = 0 and IA32_PLATFORM_ID[50] = 1
msr.lo |= (1 << 16); /* Enhanced SpeedStep Enable */
- // TODO Do we want Deep C4 and Dynamic L2 shrinking?
+ /* Enable C2E */
+ msr.lo |= (1 << 26);
+
+ /* Enable C4E */
+ msr.hi |= (1 << (32 - 32)); // C4E
+ msr.hi |= (1 << (33 - 32)); // Hard C4E
+
wrmsr(IA32_MISC_ENABLE, msr);
msr.lo |= (1 << 20); /* Lock Enhanced SpeedStep Enable */