i got a problem with my T490 - it does not reliably and in time detect that AC is unplugged.
If I remove the AC (which is USB-C on this machine) it does not detect - mostly after a view minutes it does - sometimes it does not.
The other way round - from BAT to AC is immediately recognized.
The running kernel is 5.8.5-2 but same is true for 5.7.19-2.
When I unplug I get these messages:
[14377.052592] ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PCI0.RP09.PEGP.NVDN], AE_NOT_FOUND (20200528/psargs-330) [14377.052628] ACPI Error: Aborting method \_SB.PCI0.LPCB.EC._Q27 due to previous error (AE_NOT_FOUND) (20200528/psparse-529)
monitor will print the received events for: UDEV - the event which udev sends out after rule processing KERNEL - the kernel uevent KERNEL[14375.189343] change /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:19/PNP0C09:00/PNP0C0A:00/power_supply/BAT0 (power_supply) UDEV [14376.106619] change /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:19/PNP0C09:00/PNP0C0A:00/power_supply/BAT0 (power_supply)
If at some point the system recognises its in BAT mode now I get this additional messages in udevadm:
KERNEL[14496.031770] change /devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight (backlight) UDEV [14496.033668] change /devices/pci0000:00/0000:00:02.0/drm/card0/card0-eDP-1/intel_backlight (backlight)
But tlp for example does not switch into BAT mode then still
tlp-stat -s --- TLP 1.3.1 -------------------------------------------- +++ System Info System = LENOVO ThinkPad T490 20N2004AGE BIOS = N2IET90W (1.68 ) Release = "Manjaro Linux" Kernel = 5.8.3-2-MANJARO #1 SMP PREEMPT Sat Aug 22 12:35:25 UTC 2020 x86_64 /proc/cmdline = BOOT_IMAGE=/boot/vmlinuz-5.8-x86_64 root=UUID=fc4a43ed-568f-4c5f-b70e-267676a30677 rw i915.modeset=1 i915.fastboot=1 nmi_watchdog=0 nowatchdog cryptdevice=UUID=82dce2e7-d80f-4317-a9d9-458ce4bd1e52:luks-82dce2e7-d80f-4317-a9d9-458ce4bd1e52 root=/dev/mapper/luks-82dce2e7-d80f-4317-a9d9-458ce4bd1e52 apparmor=1 security=apparmor resume=/dev/mapper/luks-dae8d075-4f8e-4bdd-a837-b2e5053c1bf3 udev.log_priority=3 Init system = systemd Boot mode = UEFI +++ TLP Status State = enabled RDW state = enabled Last run = 08:03:01, 262 sec(s) ago Mode = AC Power source = battery
But if I run
tlp start it will correctly restart in BAT mode. (PS: TLP is just a side effect it seems as I already purged and reinstalled it with fresh config)
Any ideas where else to look for debugging or even an idea how to fix it? =)