Dear Linux folks,
The Intel Broadwell-U laptop Dell Latitude E7250 (BIOS A19 01/23/2018),
according to PowerTOP, only reaches package C-State C7 and not C8, C9,
C10, while the four CPUs itself do reach C-State C10 and CE.
I was asked to look at:
1. `/sys/kernel/debug/pmc_core/package_cstate_show`
2. `/sys/kernel/debug/pmc_core/ltr`
Trying to gather statistics, after the Debian Linux kernel 5.9.1 is now
built with `INTEL_PMC_CORE=y`, `/sys/kernel/debug/pmc_core/` is still
not created despite `sudo modprobe intel_pmc_core` being successful.
(It’s not loaded automatically.)
[ 1063.644680] calling pmc_core_driver_init+0x0/0x1000
[intel_pmc_core] @ 4252
[ 1063.644721] initcall pmc_core_driver_init+0x0/0x1000
[intel_pmc_core] returned 0 after 36 usecs
The ACPI device `INT33A1` is there.
Scope (_SB)
{
Device (PEPD)
{
Name (_HID, "INT33A1" /* Intel Power Engine */) // _HID: Hardware ID
Name (_CID, EisaId ("PNP0D80") /* Windows-compatible System Power Management Controller */) // _CID: Compatible ID
Name (_UID, One) // _UID: Unique ID
Name (PEPP, Zero)
Name (DEVS, Package (0x03)
{
0x02,
Package (0x01)
{
"\\_SB.PCI0.GFX0"
},
Package (0x01)
{
"\\_SB.PCI0.SAT0.PRT1"
}
})
Name (DEVX, Package (0x08)
The table `intel_pmc_core_ids` does not contain the Broadwell-U ID
though, so I guess it’s not supported.
$ lspci -nn
00:00.0 Host bridge [0600]: Intel Corporation Broadwell-U Host Bridge -OPI [8086:1604] (rev 09)
00:02.0 VGA compatible controller [0300]: Intel Corporation HD Graphics 5500 [8086:1616] (rev 09)
00:03.0 Audio device [0403]: Intel Corporation Broadwell-U Audio Controller [8086:160c] (rev 09)
00:04.0 Signal processing controller [1180]: Intel Corporation Broadwell-U Processor Thermal Subsystem [8086:1603] (rev 09)
00:14.0 USB controller [0c03]: Intel Corporation Wildcat Point-LP USB xHCI Controller [8086:9cb1] (rev 03)
00:16.0 Communication controller [0780]: Intel Corporation Wildcat Point-LP MEI Controller #1 [8086:9cba] (rev 03)
00:19.0 Ethernet controller [0200]: Intel Corporation Ethernet Connection (3) I218-LM [8086:15a2] (rev 03)
00:1b.0 Audio device [0403]: Intel Corporation Wildcat Point-LP High Definition Audio Controller [8086:9ca0] (rev 03)
00:1c.0 PCI bridge [0604]: Intel Corporation Wildcat Point-LP PCI Express Root Port #1 [8086:9c90] (rev e3)
00:1c.3 PCI bridge [0604]: Intel Corporation Wildcat Point-LP PCI Express Root Port #4 [8086:9c96] (rev e3)
00:1d.0 USB controller [0c03]: Intel Corporation Wildcat Point-LP USB EHCI Controller [8086:9ca6] (rev 03)
00:1f.0 ISA bridge [0601]: Intel Corporation Wildcat Point-LP LPC Controller [8086:9cc3] (rev 03)
00:1f.2 SATA controller [0106]: Intel Corporation Wildcat Point-LP SATA Controller [AHCI Mode] [8086:9c83] (rev 03)
00:1f.3 SMBus [0c05]: Intel Corporation Wildcat Point-LP SMBus Controller [8086:9ca2] (rev 03)
01:00.0 SD Host controller [0805]: O2 Micro, Inc. SD/MMC Card Reader Controller [1217:8520] (rev 01)
02:00.0 Network controller [0280]: Intel Corporation Wireless 7265 [8086:095a] (rev 59)
Any idea, why the probe function `pmc_core_probe()` succeeds, despite
the code below?
cpu_id = x86_match_cpu(intel_pmc_core_ids);
if (!cpu_id)
return -ENODEV;
The watchdog driver iTCO_wdt seems to load the module `pmc_core_bxt`
despite I am unable to find the ACPI device `INT34D2` in the dissembled
AML/ASL files.
Kind regards,
Paul
