This is a note to let you know that I've just added the patch titled
intel_pstate: Fix setting VID
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
intel_pstate-fix-setting-vid.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c16ed06024a6e699c332831dd50d8276744e3de8 Mon Sep 17 00:00:00 2001
From: Dirk Brandewie <dirk.j.brandewie@xxxxxxxxx>
Date: Fri, 20 Jun 2014 07:27:58 -0700
Subject: intel_pstate: Fix setting VID
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: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/cpufreq/intel_pstate.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
--- 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 *
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 -
Patches currently in stable-queue which might be from dirk.j.brandewie@xxxxxxxxx are
queue-3.14/intel_pstate-fix-setting-vid.patch
queue-3.14/intel_pstate-update-documentation-of-max-min-_perf_pct-sysfs-files.patch
queue-3.14/intel_pstate-don-t-touch-turbo-bit-if-turbo-disabled-or-unavailable.patch
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