release/5.2.42/tools-power-turbostat-Fix-missing-SYS_LPI-counter-on.patch

From 8294f04b95c2f89f8b43f719be521b70debe1b7e Mon Sep 17 00:00:00 2001
From: Len Brown <len.brown@intel.com>
Date: Thu, 19 Mar 2020 18:26:05 -0400
Subject: [PATCH] tools/power turbostat: Fix missing SYS_LPI counter on some
 Chromebooks

commit 1f81c5efc020314b2db30d77efe228b7e117750d upstream.

Some Chromebook BIOS' do not export an ACPI LPIT, which is how
Linux finds the residency counter for CPU and SYSTEM low power states,
that is exports in /sys/devices/system/cpu/cpuidle/*residency_us

When these sysfs attributes are missing, check the debugfs attrubte
from the pmc_core driver, which accesses the same counter value.

Signed-off-by: Len Brown <len.brown@intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index eead7b44ce2f..3b7b299b7a2c 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -302,6 +302,10 @@ int *irqs_per_cpu;		/* indexed by cpu_num */
 
 void setup_all_buffers(void);
 
+char *sys_lpi_file;
+char *sys_lpi_file_sysfs = "/sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us";
+char *sys_lpi_file_debugfs = "/sys/kernel/debug/pmc_core/slp_s0_residency_usec";
+
 int cpu_is_not_present(int cpu)
 {
 	return !CPU_ISSET_S(cpu, cpu_present_setsize, cpu_present_set);
@@ -2909,8 +2913,6 @@ int snapshot_gfx_mhz(void)
  *
  * record snapshot of
  * /sys/devices/system/cpu/cpuidle/low_power_idle_cpu_residency_us
- *
- * return 1 if config change requires a restart, else return 0
  */
 int snapshot_cpu_lpi_us(void)
 {
@@ -2934,17 +2936,14 @@ int snapshot_cpu_lpi_us(void)
 /*
  * snapshot_sys_lpi()
  *
- * record snapshot of
- * /sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us
- *
- * return 1 if config change requires a restart, else return 0
+ * record snapshot of sys_lpi_file
  */
 int snapshot_sys_lpi_us(void)
 {
 	FILE *fp;
 	int retval;
 
-	fp = fopen_or_die("/sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us", "r");
+	fp = fopen_or_die(sys_lpi_file, "r");
 
 	retval = fscanf(fp, "%lld", &cpuidle_cur_sys_lpi_us);
 	if (retval != 1) {
@@ -4886,10 +4885,16 @@ void process_cpuid()
 	else
 		BIC_NOT_PRESENT(BIC_CPU_LPI);
 
-	if (!access("/sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us", R_OK))
+	if (!access(sys_lpi_file_sysfs, R_OK)) {
+		sys_lpi_file = sys_lpi_file_sysfs;
 		BIC_PRESENT(BIC_SYS_LPI);
-	else
+	} else if (!access(sys_lpi_file_debugfs, R_OK)) {
+		sys_lpi_file = sys_lpi_file_debugfs;
+		BIC_PRESENT(BIC_SYS_LPI);
+	} else {
+		sys_lpi_file_sysfs = NULL;
 		BIC_NOT_PRESENT(BIC_SYS_LPI);
+	}
 
 	if (!quiet)
 		decode_misc_feature_control();
-- 
2.7.4