Fix ASUS ExpertBook B9406 touchpad quirk never being applied

[mijuny]

Follow-up to #5435. On a fresh 3.8.2 install of an ASUS ExpertBook B9406 the touchpad is still dead: clicks register but the cursor never moves. The quirk from #5435 never took effect, for two reasons:

1. It was written to /etc/libinput/asus-expertbook-b9406.quirks. libinput reads only /etc/libinput/local-overrides.quirks and does not scan the directory, so the file was ignored.

2. The section required MatchUdevType=touchpad, but udev tags this pad as ID_INPUT_MOUSE. The bus/vendor/product/DMI keys already pin the device, so the type constraint is dropped.

How this slipped through: the original fix was verified as a manual local edit, but the packaged install path was not tested end to end, so neither defect was caught. I have since corrected that in my workflow. Both changes here were confirmed working by the reporter. Adds a migration so existing B9406 installs pick up the corrected quirk.

This restores cursor motion. A wider correction (proper touchpad classification for full gestures) will follow once I have access to a working ExpertBook again. Mine is currently physically broken (cracked screen).

AI disclaimer: diagnosed and fixed with help from Claude Code (Opus 4.8).

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds a migration + updated hardware config script to ensure the ASUS ExpertBook B9406 touchpad libinput quirk is written to the override file that libinput actually consumes, and removes the previously-written stale quirk file.

Changes:

• Add a migration that runs the ASUS B9406 touchpad fix during upgrades.
• Update the touchpad fix script to append to /etc/libinput/local-overrides.quirks (and remove the obsolete quirk file).
• Document why the previous approach did not take effect (override path + udev device type).

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
migrations/1781432360.sh	Runs the updated ASUS B9406 touchpad quirk fix during migration.
install/config/hardware/asus/fix-asus-ptl-b9406-touchpad.sh	Writes the quirk override to libinput’s override file and removes the stale file.

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[dhh]

Thanks @mijuny — the diagnosis here is right, and I verified it independently: libinput really does only read /etc/libinput/local-overrides.quirks and never scans /etc, so the file from #5435 was dead on arrival.

Superseded by #6388, which targets quattro (this branch was cut against dev) and carries your commits' authorship.

Two changes there worth knowing about:

• Drop-in instead of appending to local-overrides.quirks. libinput scandirs /usr/share/libinput for any *.quirks file, so we can own a file outright and rewrite it wholesale. Appending to the shared override file means idempotency has to grep for a section we already wrote, which silently pins the first version we ever ship — if the quirk ever needs correcting, the fix never lands.
• Quattro porting. install/hardware/* runs as root there, so the sudo calls come out; migrations run as the user, so the migration escalates explicitly rather than sourcing the leaf; and the migration timestamp needed renumbering above quattro's newest.

Kept your MatchUdevType removal, though I flagged in the new PR that the evidence for it is weaker than for the path fix — both changes shipped in the same test, so the reporter's confirmation can't separate them. It costs nothing if unnecessary.

Hope the ExpertBook gets a new screen soon — a confirmation on live hardware before #6388 merges would still be valuable.