functions: use iw for Wi-Fi power saving

[Junjie650]

The powersave profiles currently use iwpriv, which Fedora no longer
installs. Consequently, applying those profiles does not enable Wi-Fi
power saving.

Use the nl80211-based iw dev IFACE set power_save on|off command for
modern drivers. If iw is unavailable or rejects an interface, retain
the existing iwpriv path for legacy Wireless Extensions drivers. The
existing sysfs fallback is unchanged.

This also adds iw to the RPM requirements and covers the following
cases with unit tests:

• enabling and disabling power saving;
• multiple wireless interfaces;
• missing iw;
• per-interface iw failure and iwpriv fallback;
• missing tools;
• systems with no wireless interfaces.

Validation:

• all 116 unit tests pass;
• the modified shell helper passes ShellCheck;
• the new test passes the project's error-only pylint check;
• tuned.spec expands successfully with Fedora 45 RPM macros;
• a local nl80211 interface reports its power-save state through the
  same iw command family.

Fixes #836

Resolves: rhbz#2372365

[coderabbitai]

📝 Walkthrough

Summary by CodeRabbit

• Bug Fixes

  • Improved Wi‑Fi power-save configuration across supported wireless interfaces.
  • Added compatibility with modern iw tools and fallback support for legacy drivers.
  • Gracefully handles missing wireless interfaces or configuration tools without failing.
  • Correctly applies enabled and disabled power-save states, including legacy settings.

• Tests

  • Added coverage for Wi‑Fi power-save behavior, fallback handling, interface compatibility, and unavailable environments.

Walkthrough

_wifi_set_power_level now prefers iw, falls back to iwpriv, handles missing wireless support, and writes quoted sysfs values. The package requires iw. Unit tests cover enable, disable, fallback, and absent-resource cases.

Changes

Wi-Fi power-save configuration

Layer / File(s)	Summary
Power-save command selection and packaging functions, tuned.spec	The function maps levels 0 and 6 to off, uses iw when available, falls back to iwpriv, and updates sysfs with quoted values. The package adds iw as a runtime requirement.
Power-save behavior validation tests/unit/test_functions.py	Tests validate command selection for all interfaces, fallback after unavailable or failed iw, missing tools, missing interfaces, and the test entry point.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Sequence Diagram(s)

sequenceDiagram
  participant _wifi_set_power_level
  participant iw
  participant iwpriv
  participant sysfs
  _wifi_set_power_level->>iw: Set power_save for each interface
  iw-->>_wifi_set_power_level: Unavailable or command failure
  _wifi_set_power_level->>iwpriv: Apply legacy configuration
  _wifi_set_power_level->>sysfs: Write quoted power_level value

Loading

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Description check	✅ Passed	The description clearly explains the Wi-Fi power-saving change, fallback behavior, dependency update, tests, and validation.
Linked Issues check	✅ Passed	The description links issue #836 and rhbz#2372365, and the changes directly address the reported Wi-Fi power-saving problem.
Out of Scope Changes check	✅ Passed	The implementation, tests, and RPM dependency update directly support the stated Wi-Fi power-saving objective.
Title check	✅ Passed	The title clearly and concisely identifies the main change: using iw for Wi-Fi power saving.

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@functions`:
- Around line 312-317: Update the power_save assignment near the iw interface
loop so level 6 produces off, matching its definition in the surrounding
configuration instead of enabling power saving. Preserve existing mappings for
other levels and add coverage invoking _run(6) to verify the resulting
power-save setting is off.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro Plus

Run ID: 34c8c78c-7214-40f6-9b6b-e0bffe4a5be0

📥 Commits

Reviewing files that changed from the base of the PR and between 0eb28ac and 44c05df.

📒 Files selected for processing (3)

• functions
• tests/unit/test_functions.py
• tuned.spec

[yarda]

Thanks, LGTM.