releases/4.19.34/cpufreq-acpi-cpufreq-report-if-cpu-doesn-t-support-b.patch

   1 From 859ec1ddd6a82520744e8c25c3b1611385a1a299 Mon Sep 17 00:00:00 2001
   2 From: Erwan Velu <erwanaliasr1@gmail.com>
   3 Date: Wed, 20 Feb 2019 11:10:17 +0100
   4 Subject: cpufreq: acpi-cpufreq: Report if CPU doesn't support boost
   5  technologies
   6
   7 [ Upstream commit 1222d527f314c86a3b59a522115d62facc5a7965 ]
   8
   9 There is some rare cases where CPB (and possibly IDA) are missing on
  10 processors.
  11
  12 This is the case fixed by commit f7f3dc00f612 ("x86/cpu/AMD: Fix
  13 erratum 1076 (CPB bit)") and following.
  14
  15 In such context, the boost status isn't reported by
  16 /sys/devices/system/cpu/cpufreq/boost.
  17
  18 This commit is about printing a message to report that the CPU
  19 doesn't expose the boost capabilities.
  20
  21 This message could help debugging platforms hit by this phenomena.
  22
  23 Signed-off-by: Erwan Velu <e.velu@criteo.com>
  24 [ rjw: Change the message text somewhat ]
  25 Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
  26 Signed-off-by: Sasha Levin <sashal@kernel.org>
  27 ---
  28  drivers/cpufreq/acpi-cpufreq.c | 4 +++-
  29  1 file changed, 3 insertions(+), 1 deletion(-)
  30
  31 diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
  32 index b61f4ec43e06..aca30f45172e 100644
  33 --- a/drivers/cpufreq/acpi-cpufreq.c
  34 +++ b/drivers/cpufreq/acpi-cpufreq.c
  35 @@ -911,8 +911,10 @@ static void __init acpi_cpufreq_boost_init(void)
  36  {
  37         int ret;
  38
  39 -       if (!(boot_cpu_has(X86_FEATURE_CPB) || boot_cpu_has(X86_FEATURE_IDA)))
  40 +       if (!(boot_cpu_has(X86_FEATURE_CPB) || boot_cpu_has(X86_FEATURE_IDA))) {
  41 +               pr_debug("Boost capabilities not present in the processor\n");
  42                 return;
  43 +       }
  44
  45         acpi_cpufreq_driver.set_boost = set_boost;
  46         acpi_cpufreq_driver.boost_enabled = boost_state(0);
  47 --
  48 2.19.1
  49