[PATCH i-g-t v10 0/2] tests/intel/xe_pm_residency: Add ASPM Link residency test

[Karthik Poosa <karthik.poosa@intel.com>]

Add subtest aspm_link_residency to xe_pm_residency test to check ASPM Link state residency.
This uses the debugfs /sys/kernel/debug/dri/0/dgfx_pcie_link_residencies to read the
residency counters.
Add an API igt_device_get_pci_usp() to get pcie device's upstream port.

v2:
 - Avoid using igt_require() in igt_device_get_pci_device. (Kamil)
 - Add description about PCIe ASPM in commit message and code. (Kamil)
 - Resolve couple of compilation warnings about using variable as format string to sscanf.

v3:
 - Rename igt_device_get_pci_usp() to igt_device_get_pci_upstream_port(). (Kamil)

v4:
 - Refactor and enhance readability. (Badal)
 - Move save and restore of link states to separate functions. (Badal)

v5:
 - Use device type from pci express capability of pci config space to
   identify upstream port. (Badal)

v6:
 - Search for upstream port only two levels up of the endpoint as we want to
   verify ASPM only on PCIe link on which GPU card is present.
 - Skip test for integrated platforms.

v7:
 - Address below review comments from Riana.
 - Use igt_sysfs_has_attr() instead of faccess().
 - Remove unnecessary spaces, debug logs, if checks.
 - Wrap line length to 100 chars.
 - Use spinner instead of mmap as workload.

v8:
 - Address minor review comments from Kamil.

Karthik Poosa (2):
  lib/igt_device: Add API to get pci device upstream port
  tests/intel/xe_pm_residency: Add subtest for ASPM Link state residency

 lib/igt_device.c              |  43 +++++++++
 lib/igt_device.h              |   1 +
 lib/igt_pci.h                 |   2 +
 tests/intel/xe_pm_residency.c | 176 ++++++++++++++++++++++++++++++++++
 4 files changed, 222 insertions(+)

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2.25.1