[PATCH 3.13 071/259] intel_pstate: Fix setting VID
From: Kamal Mostafa
Date: Fri Aug 08 2014 - 16:51:23 EST
3.13.11.6 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>
commit c16ed06024a6e699c332831dd50d8276744e3de8 upstream.
Commit 21855ff5 (intel_pstate: Set turbo VID for BayTrail) introduced
setting the turbo VID which is required to prevent a machine check on
some Baytrail SKUs under heavy graphics based workloads. The
docmumentation update that brought the requirement to light also
changed the bit mask used for enumerating P state and VID values from
0x7f to 0x3f.
This change returns the mask value to 0x7f.
Tested with the Intel NUC DN2820FYK,
BIOS version FYBYT10H.86A.0034.2014.0513.1413 with v3.16-rc1 and
v3.14.8 kernel versions.
Fixes: 21855ff5 (intel_pstate: Set turbo VID for BayTrail)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=77951
Reported-and-tested-by: Rune Reterson <rune@xxxxxxxxxxxx>
Reported-and-tested-by: Eric Eickmeyer <erich@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
drivers/cpufreq/intel_pstate.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index bbfb81f..37ef477 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -361,21 +361,21 @@ static int byt_get_min_pstate(void)
{
u64 value;
rdmsrl(BYT_RATIOS, value);
- return (value >> 8) & 0x3F;
+ return (value >> 8) & 0x7F;
}
static int byt_get_max_pstate(void)
{
u64 value;
rdmsrl(BYT_RATIOS, value);
- return (value >> 16) & 0x3F;
+ return (value >> 16) & 0x7F;
}
static int byt_get_turbo_pstate(void)
{
u64 value;
rdmsrl(BYT_TURBO_RATIOS, value);
- return value & 0x3F;
+ return value & 0x7F;
}
static void byt_set_pstate(struct cpudata *cpudata, int pstate)
@@ -409,8 +409,8 @@ static void byt_get_vid(struct cpudata *cpudata)
rdmsrl(BYT_VIDS, value);
- cpudata->vid.min = int_tofp((value >> 8) & 0x3f);
- cpudata->vid.max = int_tofp((value >> 16) & 0x3f);
+ cpudata->vid.min = int_tofp((value >> 8) & 0x7f);
+ cpudata->vid.max = int_tofp((value >> 16) & 0x7f);
cpudata->vid.ratio = div_fp(
cpudata->vid.max - cpudata->vid.min,
int_tofp(cpudata->pstate.max_pstate -
--
1.9.1
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