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Subject[PATCH 5.5 15/46] tools/power turbostat: Fix missing SYS_LPI counter on some Chromebooks
Date
From: Len Brown <len.brown@intel.com>

[ Upstream commit 1f81c5efc020314b2db30d77efe228b7e117750d ]

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: Sasha Levin <sashal@kernel.org>
---
tools/power/x86/turbostat/turbostat.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 78507cd479bb4..17e82eaf5c4f4 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -304,6 +304,10 @@ 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);
@@ -2916,8 +2920,6 @@ 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)
{
@@ -2941,17 +2943,14 @@ 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) {
@@ -4907,10 +4906,16 @@ 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();
--
2.20.1


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