diff options
Diffstat (limited to 'resources/coreboot/default/patches/0019-fix-speedstep-on-x200-t400-Revert-cpu-intel-model_10.patch')
| -rw-r--r-- | resources/coreboot/default/patches/0019-fix-speedstep-on-x200-t400-Revert-cpu-intel-model_10.patch | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/resources/coreboot/default/patches/0019-fix-speedstep-on-x200-t400-Revert-cpu-intel-model_10.patch b/resources/coreboot/default/patches/0019-fix-speedstep-on-x200-t400-Revert-cpu-intel-model_10.patch new file mode 100644 index 0000000..3b1bd40 --- /dev/null +++ b/resources/coreboot/default/patches/0019-fix-speedstep-on-x200-t400-Revert-cpu-intel-model_10.patch @@ -0,0 +1,47 @@ +From 3cf315fd59f1388d60cce9290eb52bccb7b29625 Mon Sep 17 00:00:00 2001 +From: Leah Rowe <leah@libreboot.org> +Date: Wed, 1 Dec 2021 02:53:00 +0000 +Subject: [PATCH 1/2] 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 315e7c36fc..1423fd72bc 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 +-- +2.40.0 + |