On a Samsung Ultra Book 4 running Ubuntu 24.04 with kernel version 6.8.0-51-generic, the battery fails to be detected when the system boots on battery power. No directory is created under /sys/class/power_supply/BAT1. However, if the system boots while connected to a power source, the battery is detected correctly. Steps to Reproduce: Power off the laptop. Disconnect the charger and boot the system on battery power. Observe that /sys/class/power_supply/BAT1 is missing. Additional Details: Running acpidbg shows the battery is correctly handled by ACPI in both states (on battery or plugged in), suggesting an issue with the kernel's battery initialization during boot when on battery power. Expected Behavior: The battery should be detected and /sys/class/power_supply/BAT1 should be created regardless of whether the system is booted on battery or connected to a power source.
Additionally, upgrading kernel to 6.12.3 (latest stable ubuntu) did not fix the issue.
Has any kernel ever worked for you, or has it always been like this?
Created attachment 307420 [details] dmesg boot logs on AC Booting when AC connected Shell prompt : sudo dmesg | grep -i BAT > dmesg_acpi_bus_log_no_ac.txt I first enabled dynamic debug by adding dyndbg="file drivers/acpi/bus.c +pfsl" to my grub config file.
Created attachment 307421 [details] dmesg boot logs no AC Dmesg at boot time when no AC source plugged Shell prompt : sudo dmesg | grep -i BAT > dmesg_acpi_bus_log_no_ac.txt I first enabled dynamic debug for drivers/acpi/bus.c file with dyndbg="file drivers/acpi/bus.c +pfsl" in my grub config.
It has always been like this. From the above attachment, it looms like the BAT1._STA methods is taking a long time to go to 0x1F value when on battery. Maybe some firmware bug.
Do you still have Windows installed? Can you confirm it's not affected?
(In reply to Artem S. Tashkinov from comment #6) > Do you still have Windows installed? Can you confirm it's not affected? Yes, I have a dual boot. Indeed, Windows is not affected. Also, all firmware and drivers are up to date on Windows side.
Please give kernel 6.13-rc5 a try.