On 9/27/24 10:19, Guenter Roeck wrote:
Copying devicetree maintainers.

On Thu, Sep 26, 2024 at 09:39:38PM -0700, Guenter Roeck wrote:
On Thu, Sep 26, 2024 at 09:14:11PM -0700, Guenter Roeck wrote:
Hi Stephen,

On Thu, Jul 18, 2024 at 02:05:07PM -0700, Stephen Boyd wrote:
Test that clks registered with 'struct clk_parent_data' work as
intended and can find their parents.


When testing this on arm64, I see the error below. The error is only
seen if I boot through efi, i.e., with "-bios QEMU_EFI-aarch64.fd"
qemu parameter.

Any idea what might cause the problem ?

I noticed that the new overlay tests fail as well, also with "path '/' not
found".

[Maybe] answering my own question: I think the problem may be that there
is no devicetree file and thus no devicetree root when booting through
efi (in other words, of_root is NULL). Would it make sense to skip the
tests in that case ?


The problem is that of_root is not initialized in arm64 boots if ACPI
is enabled.

 From arch/arm64/kernel/setup.c:setup_arch():

        if (acpi_disabled)
                unflatten_device_tree();                // initializes of_root

ACPI is enabled if the system boots from EFI. This also affects
CONFIG_OF_KUNIT_TEST, which explicitly checks if of_root exists and
fails the test if it doesn't.

I think those tests need to add a check for this condition, or affected
machines won't be able to run those unit tests. The obvious solution would
be to check if of_root is set, but then the associated test case in
CONFIG_OF_KUNIT_TEST would not make sense.

Any suggestions ?


Would it work if these tests check if acpi_disabled and skip if it isn't
disabled? It might be low overhead condition to check from these tests.

acpi_disabled is exported:

arch/arm64/kernel/acpi.c:EXPORT_SYMBOL(acpi_disabled);
arch/loongarch/kernel/acpi.c:EXPORT_SYMBOL(acpi_disabled);
arch/riscv/kernel/acpi.c:EXPORT_SYMBOL(acpi_disabled);
arch/x86/kernel/acpi/boot.c:EXPORT_SYMBOL(acpi_disabled);

thanks,
-- Shuah


Reply via email to