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authorGeorge Cherian <george.cherian@cavium.com>2018-03-23 03:30:31 -0700
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-03-30 12:15:58 +0200
commit3d41386d556db9f720e00de3e11e45f39cb5071c (patch)
tree3b04b6dfe0445d3e13f2ba7da722011a6fec894a /drivers/cpufreq
parenta8b6966034ba88190eca397e2693b5bc16790517 (diff)
cpufreq: CPPC: Use transition_delay_us depending transition_latency
With commit e948bc8fbee0 (cpufreq: Cap the default transition delay value to 10 ms) the cpufreq was not honouring the delay passed via ACPI (PCCT). Due to which on ARM based platforms using CPPC the cpufreq governor tries to change the frequency of CPUs faster than expected. This leads to continuous error messages like the following. " ACPI CPPC: PCC check channel failed. Status=0 " Earlier (without above commit) the default transition delay was taken form the value passed from PCCT. Use the same value provided by PCCT to set the transition_delay_us. Fixes: e948bc8fbee0 (cpufreq: Cap the default transition delay value to 10 ms) Signed-off-by: George Cherian <george.cherian@cavium.com> Cc: 4.14+ <stable@vger.kernel.org> # 4.14+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cppc_cpufreq.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
index 8f7b21a4d537..8300a9fcb80c 100644
--- a/drivers/cpufreq/cppc_cpufreq.c
+++ b/drivers/cpufreq/cppc_cpufreq.c
@@ -20,6 +20,7 @@
#include <linux/cpu.h>
#include <linux/cpufreq.h>
#include <linux/dmi.h>
+#include <linux/time.h>
#include <linux/vmalloc.h>
#include <asm/unaligned.h>
@@ -162,6 +163,8 @@ static int cppc_cpufreq_cpu_init(struct cpufreq_policy *policy)
policy->cpuinfo.max_freq = cppc_dmi_max_khz;
policy->cpuinfo.transition_latency = cppc_get_transition_latency(cpu_num);
+ policy->transition_delay_us = cppc_get_transition_latency(cpu_num) /
+ NSEC_PER_USEC;
policy->shared_type = cpu->shared_type;
if (policy->shared_type == CPUFREQ_SHARED_TYPE_ANY)