diff options
Diffstat (limited to 'config/coreboot/default/patches/0014-fix-speedstep-on-x200-t400-Revert-cpu-intel-model_10.patch')
| -rw-r--r-- | config/coreboot/default/patches/0014-fix-speedstep-on-x200-t400-Revert-cpu-intel-model_10.patch | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/config/coreboot/default/patches/0014-fix-speedstep-on-x200-t400-Revert-cpu-intel-model_10.patch b/config/coreboot/default/patches/0014-fix-speedstep-on-x200-t400-Revert-cpu-intel-model_10.patch new file mode 100644 index 00000000..bfcc486a --- /dev/null +++ b/config/coreboot/default/patches/0014-fix-speedstep-on-x200-t400-Revert-cpu-intel-model_10.patch @@ -0,0 +1,47 @@ +From c53e5035b612710595abc93f0b4c3c65ca61ebad Mon Sep 17 00:00:00 2001 +From: Leah Rowe <leah@libreboot.org> +Date: Wed, 1 Dec 2021 02:53:00 +0000 +Subject: [PATCH 14/39] fix speedstep on x200/t400: Revert + "cpu/intel/model_1067x: enable PECI" + +This reverts commit 70fea013c7ebd6d85a7806748233fcfd76802f5f. + +Enabling PECI without microcode updates loaded causes the CPUID feature set +to become corrupted. And one consequence is broken SpeedStep. At least, that's +my understanding looking at Intel Errata. This revert is not a fix, because +upstream is correct (upstream assumes microcode updates). We will simply +maintain this revert patch in Libreboot, from now on. +--- + src/cpu/intel/model_1067x/model_1067x_init.c | 9 --------- + 1 file changed, 9 deletions(-) + +diff --git a/src/cpu/intel/model_1067x/model_1067x_init.c b/src/cpu/intel/model_1067x/model_1067x_init.c +index d051e8915b..30ba2bf0c6 100644 +--- a/src/cpu/intel/model_1067x/model_1067x_init.c ++++ b/src/cpu/intel/model_1067x/model_1067x_init.c +@@ -141,8 +141,6 @@ static void configure_emttm_tables(void) + wrmsr(MSR_EMTTM_CR_TABLE(5), msr); + } + +-#define IA32_PECI_CTL 0x5a0 +- + static void configure_misc(const int eist, const int tm2, const int emttm) + { + msr_t msr; +@@ -185,13 +183,6 @@ static void configure_misc(const int eist, const int tm2, const int emttm) + msr.lo |= (1 << 20); /* Lock Enhanced SpeedStep Enable */ + wrmsr(IA32_MISC_ENABLE, msr); + } +- +- /* Enable PECI +- WARNING: due to Erratum AW67 described in Intel document #318733 +- the microcode must be updated before this MSR is written to. */ +- msr = rdmsr(IA32_PECI_CTL); +- msr.lo |= 1; +- wrmsr(IA32_PECI_CTL, msr); + } + + #define PIC_SENS_CFG 0x1aa +-- +2.39.2 + |