This is a note to let you know that I've just added the patch titled
cpufreq: intel_pstate: Fix processing for turbo activation ratio
to the 4.4-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:
cpufreq-intel_pstate-fix-processing-for-turbo-activation-ratio.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 1becf03545a0859ceaaf9e8c2d9861882a71cb01 Mon Sep 17 00:00:00 2001
From: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
Date: Fri, 22 Apr 2016 19:53:59 -0700
Subject: cpufreq: intel_pstate: Fix processing for turbo activation ratio
From: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
commit 1becf03545a0859ceaaf9e8c2d9861882a71cb01 upstream.
When the config TDP level is not nominal (level = 0), the MSR values for
reading level 1 and level 2 ratios contain power in low 14 bits and actual
ratio bits are at bits [23:16]. The current processing for level 1 and
level 2 is wrong as there is no shift done to get actual ratio.
Fixes: 6a35fc2d6c22 (cpufreq: intel_pstate: get P1 from TAR when available)
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/cpufreq/intel_pstate.c | 5 +++++
1 file changed, 5 insertions(+)
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -667,6 +667,11 @@ static int core_get_max_pstate(void)
if (err)
goto skip_tar;
+ /* For level 1 and 2, bits[23:16] contain the ratio */
+ if (tdp_ctrl)
+ tdp_ratio >>= 16;
+
+ tdp_ratio &= 0xff; /* ratios are only 8 bits long */
if (tdp_ratio - 1 == tar) {
max_pstate = tar;
pr_debug("max_pstate=TAC %x\n", max_pstate);
Patches currently in stable-queue which might be from srinivas.pandruvada@xxxxxxxxxxxxxxx are
queue-4.4/cpufreq-intel_pstate-fix-processing-for-turbo-activation-ratio.patch
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