tools/power turbostat: Warn on bad ACPI LPIT data

On some systems /sys/devices/system/cpu/cpuidle/low_power_idle_cpu_residency_us
or /sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us
return a file error because of bad ACPI LPIT data from a misconfigured BIOS.
turbostat interprets this failure as a fatal error and outputs

	turbostat: CPU LPI: No data available

If the ACPI LPIT sysfs files return an error output a warning instead of
a fatal error, disable the ACPI LPIT evaluation code, and continue.

Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 10 insertions, 5 deletions

diff --git a/tools/power/x86/turbostat/turbostat.c b/tools/power/x86/turbostat/turbostat.c
index 9817abd215b9..442af7892402 100644
--- a/tools/power/x86/turbostat/turbostat.c
+++ b/tools/power/x86/turbostat/turbostat.c
@@ -2921,8 +2921,11 @@ int snapshot_cpu_lpi_us(void)
         fp = fopen_or_die("/sys/devices/system/cpu/cpuidle/low_power_idle_cpu_residency_us", "r");
 
         retval = fscanf(fp, "%lld", &cpuidle_cur_cpu_lpi_us);
-        if (retval != 1)
-                err(1, "CPU LPI");
+        if (retval != 1) {
+                fprintf(stderr, "Disabling Low Power Idle CPU output\n");
+                BIC_NOT_PRESENT(BIC_CPU_LPI);
+                return -1;
+        }
 
         fclose(fp);
 
@@ -2944,9 +2947,11 @@ int snapshot_sys_lpi_us(void)
         fp = fopen_or_die("/sys/devices/system/cpu/cpuidle/low_power_idle_system_residency_us", "r");
 
         retval = fscanf(fp, "%lld", &cpuidle_cur_sys_lpi_us);
-        if (retval != 1)
-                err(1, "SYS LPI");
-
+        if (retval != 1) {
+                fprintf(stderr, "Disabling Low Power Idle System output\n");
+                BIC_NOT_PRESENT(BIC_SYS_LPI);
+                return -1;
+        }
         fclose(fp);
 
         return 0;