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authorJeremy Compostella <jeremy.compostella@intel.com>2022-07-21 14:08:08 -0700
committerPaul Fagerburg <pfagerburg@chromium.org>2022-07-28 14:57:59 +0000
commitcd6a2ad1b2d3444e815fb9b1a6ec1c98e0403c23 (patch)
tree1b5d0397789bfef4363c84d28b2b75d3c2945a51
parent117770d32468e63df37aee1c041b5dc7cc1d56d2 (diff)
soc/intel/alderlake: Set Energy Perf Bias appropriate default value
The current "normal" EPB (six) setting resulted in the desired out of box power and performance for several CPU generations. However, a power and performance analysis on Alder Lake and Raptor Lake CPUs demonstrates that this value results in undesirable higher uncore power and that seven is a more appropriate value. Note: the Linux kernel "4ecc933b x86: intel_epb: Allow model specific normal EPB value" patch sets the EPB to 7 for Alder Lake. BRANCH=firmware-brya-14505.B BUG=b:239853069 TEST=verify that EPB is set by coreboot Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com> Change-Id: I5784656903d4c58bedc5063ee3ef310a99711050 Reviewed-on: https://review.coreboot.org/c/coreboot/+/66059 Reviewed-by: Michał Żygowski <michal.zygowski@3mdeb.com> Reviewed-by: Cliff Huang <cliff.huang@intel.com> Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
-rw-r--r--src/soc/intel/alderlake/cpu.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/src/soc/intel/alderlake/cpu.c b/src/soc/intel/alderlake/cpu.c
index 7308185be7..f9e8f6f2fa 100644
--- a/src/soc/intel/alderlake/cpu.c
+++ b/src/soc/intel/alderlake/cpu.c
@@ -129,8 +129,9 @@ void soc_core_init(struct device *cpu)
/* Enable Direct Cache Access */
configure_dca_cap();
- /* Set energy policy */
- set_energy_perf_bias(ENERGY_POLICY_NORMAL);
+ /* Set energy policy. The "normal" EPB (6) is not suitable for Alder
+ * Lake or Raptor Lake CPUs, as this results in higher uncore power. */
+ set_energy_perf_bias(7);
const config_t *conf = config_of_soc();
/* Set energy-performance preference */