Greetings. I have a problem with a certain x86 laptop, and judging from the kernel's output, this looks very much like a broken ACPI table. Versions tried are 5.3.8 (Fedora31 liveimage), 5.5.2 (openSUSE Tumbleweed installer) and 5.6.0-rc1+ (b19e8c68470385dd2c5440876591fddb02c8c402; self compile), all exhibiting the same hang. The last messages emitted by 5.6.0-rc1+ are: ACPI: 11 ACPI AML tables successfully acquired and loaded ACPI: EC: EC started ACPI: EC: interrupt blocked ACPI: \: Used as first EC ACPI: \: GPE=0x10, IRQ=-1, EC_CMD/EC_SC=0x66, EC_DATA=0x62 ACPI: EC: Boot ECDT EC used to handle transactions <hang> The full boot procedure is made available at http://inai.de/files/m921.mp4 [79MB]. Curiously, FreeBSD 12.1 can be booted without issues, so either they already workaround the issue, or don't trigger it in the first place. After about 20 minutes, the kernel issues a stack trace. http://inai.de/files/m922.mp4 [4.2M]; this seems to repeat every 20 minutes: Task swapper blocked for more than 491 seconds. schedule schedule_timeout __down_timeout down_timeout acpi_os_wait_semaphore acpi_ex_system_wait_semaphore acpi_ev_acquire_global_lock acpi_ex_acquire_mutex_object acpi_ex_acquire_global_lock acpi_ex_write_data_to_field acpi_ex_store_object_to_node acpi_ex_store acpi_ex_opcode_1A_1T_1R acpi_ds_exec_end_op acpi_ps_parse_loop [a few frames more] For comparison, a (vastly) different laptop with a proper firmware, the EC messages go like this: <Fujitsu U728 for comparison> ACPI: EC: EC started ACPI: EC: interrupt blocked ACPI: \_SB_.PCI0.LPCB.EC__: Used as first EC ACPI: \_SB_.PCI0.LPCB.EC__: GPE=0x22, EC_CMD/EC_SC=0x66, EC_DATA=0x62 ACPI: \_SB_.PCI0.LPCB.EC__: Boot DSDT EC used to handle transactions ACPI: Interpreter enabled It kind of makes sense that, if "\" is seen as an EC in the Medion that it is not going to work.
