linux/tools/power
Chen Yu 227ed18f45 tools/power turbostat: Do not print negative LPI residency
turbostat prints the abnormal SYS%LPI across suspend-to-idle:
SYS%LPI = 114479815993277.50

This is reproduced by:
Run a freeze cycle, e.g. "sleepgraph -m freeze -rtcwake 15".
Then do a reboot. After boot up, launch the suspend-idle-idle
and check the SYS%LPI field.

The slp_so residence counter is in LPIT table, and BIOS does not
clears this register across reset. The PMC expects the OS to calculate
the LPI residency based on the delta. However, there is an firmware
issue that the LPIT gets cleared to 0 during the second suspend
to idle after the reboot, which brings negative delta value.

[lenb: updated to print "neg" upon this BIOS failure]

Reported-by: Todd Brandt <todd.e.brandt@intel.com>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2024-01-12 12:43:19 -06:00
..
acpi ACPICA: Update all copyrights/signons to 2023 2023-04-06 20:29:11 +02:00
cpupower cpupower: fix reference to nonexistent document 2023-10-25 10:14:35 -06:00
pm-graph PM: tools: Fix sleepgraph syntax error 2023-11-20 17:59:58 +01:00
x86 tools/power turbostat: Do not print negative LPI residency 2024-01-12 12:43:19 -06:00