[RFC PATCH 0/2] Add a test to verify device probing on ACPI platforms

[Laura Nao]

Regressions that prevent a driver from probing a device can significantly
affect the functionality of a platform.

A kselftest to verify if devices on a DT-based platform are probed
correctly was recently introduced [1], but no such generic test is
available for ACPI platforms yet. bootrr [2]  provides device probe
testing, but relies on a pre-defined list of the peripherals present on
each DUT.

On ACPI based hardware, a complete description of the platform is
provided to the OS by the system firmware. ACPI namespace objects are
mapped by the Linux ACPI subsystem into a device tree in
/sys/devices/LNXSYSTEM:00; the information in this subtree can be parsed
to build a list of the hw peripherals present on the DUT dynamically.

This series adds a test to verify if the devices declared in the ACPI
namespace and supported by the kernel are probed correctly.

This work follows a similar approach to [1], adapted for the ACPI use
case.

The first patch introduces a script that builds a list of all ACPI device
IDs supported by the kernel, by inspecting the acpi_device_id structs in
the sources. This list can be used to avoid testing ACPI-enumerated
devices that don't have a matching driver in the kernel. This script was
highly inspired by the dt-extract-compatibles script [3].

In the second patch, a new kselftest is added. It parses the
/sys/devices/LNXSYSTEM:00 tree to obtain a list of all platform
peripherals and verifies which of those, if supported, are correctly
bound to a driver.

Feedback is much appreciated,

Thank you,

Laura

[1] https://lore.kernel.org/all/20230828211424.2964562-1-nfraprado@xxxxxxxxxxxxx/
[2] https://github.com/kernelci/bootr
[3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/dtc/dt-extract-compatibles

Laura Nao (2):
  acpi: Add script to extract ACPI device ids in the kernel
  kselftest: Add test to detect unprobed devices on ACPI platforms

 MAINTAINERS                                   |  2 +
 scripts/acpi/acpi-extract-ids                 | 60 +++++++++++++++
 tools/testing/selftests/Makefile              |  1 +
 tools/testing/selftests/acpi/.gitignore       |  2 +
 tools/testing/selftests/acpi/Makefile         | 23 ++++++
 .../selftests/acpi/test_unprobed_devices.sh   | 75 +++++++++++++++++++
 6 files changed, 163 insertions(+)
 create mode 100755 scripts/acpi/acpi-extract-ids
 create mode 100644 tools/testing/selftests/acpi/.gitignore
 create mode 100644 tools/testing/selftests/acpi/Makefile
 create mode 100755 tools/testing/selftests/acpi/test_unprobed_devices.sh

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