diff options
| author | Tristan Corrick <tristan@corrick.kiwi> | 2018-10-31 02:27:12 +1300 |
|---|---|---|
| committer | Nico Huber <nico.h@gmx.de> | 2018-11-01 22:23:21 +0000 |
| commit | fdf907e4405e5df84e9d5a29735e0506782d9c6d (patch) | |
| tree | 76da8301ef861c1827d5280a67e75160019dda0f /src/cpu/intel | |
| parent | ba8ead817dad9be5e3afa0a702d888d4a48a640d (diff) | |
cpu/intel/haswell: Only change the slow ramp rate for ULT CPUs
On my system (Pentium G3258, ASRock H81M-HDS), changing the the slow
ramp rate during `initialize_vr_config()` results in the following
exception, causing the system to hang.
CPU Index 0 - APIC 0 Unexpected Exception:13 @ 10:7f7a3736 - Halting
Code: 0 eflags: 00010006 cr2: 00000000
eax: 00262626 ebx: 00140000 ecx: 00000603 edx: 00360000
edi: 00000007 esi: 00262626 ebp: 7f7c0fd8 esp: 7f7c0e90
So, only change this setting for Haswell ULT CPUs, as suggested by the
BIOS Writer's guide.
Change-Id: I79b10139295741d298ac6c77c4f7272ac151ad90
Signed-off-by: Tristan Corrick <tristan@corrick.kiwi>
Reviewed-on: https://review.coreboot.org/29384
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Diffstat (limited to 'src/cpu/intel')
| -rw-r--r-- | src/cpu/intel/haswell/haswell_init.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/src/cpu/intel/haswell/haswell_init.c b/src/cpu/intel/haswell/haswell_init.c index c67ef1438d..2340dd0b03 100644 --- a/src/cpu/intel/haswell/haswell_init.c +++ b/src/cpu/intel/haswell/haswell_init.c @@ -333,9 +333,11 @@ static void initialize_vr_config(void) msr.hi &= ~(1 << (51 - 32)); /* Enable decay mode on C-state entry. */ msr.hi |= (1 << (52 - 32)); - /* Set the slow ramp rate to be fast ramp rate / 4 */ - msr.hi &= ~(0x3 << (53 - 32)); - msr.hi |= (0x01 << (53 - 32)); + if (haswell_is_ult()) { + /* Set the slow ramp rate to be fast ramp rate / 4 */ + msr.hi &= ~(0x3 << (53 - 32)); + msr.hi |= (0x01 << (53 - 32)); + } /* Set MIN_VID (31:24) to allow CPU to have full control. */ msr.lo &= ~0xff000000; wrmsr(MSR_VR_MISC_CONFIG, msr); |