Re: Linux hangs at ACPI init on Medion P15648 MD63490

["Rafael J. Wysocki" <rafael@kernel.org>]

On Fri, Feb 14, 2020 at 8:28 PM Jan Engelhardt <jengelh@inai.de> wrote:
>
> 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.

Would it be possible to try 5.0 or earlier on the problematic machine?

You may be hitting a regression here.

> 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.