Patch "cpufreq: intel_pstate: Fix processing for turbo activation ratio" has been added to the 4.4-stable tree

Patch "cpufreq: intel_pstate: Fix processing for turbo activation ratio" has been added to the 4.4-stable tree

[gregkh]

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@vger.kernel.org> know about it.


>From 1becf03545a0859ceaaf9e8c2d9861882a71cb01 Mon Sep 17 00:00:00 2001
From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Date: Fri, 22 Apr 2016 19:53:59 -0700
Subject: cpufreq: intel_pstate: Fix processing for turbo activation ratio

From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

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@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 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@linux.intel.com are

queue-4.4/cpufreq-intel_pstate-fix-processing-for-turbo-activation-ratio.patch