[Bug 221238] lg-laptop: Spurious ACK and dropped keystrokes caused by ACPI method calls conflicting with i8042 driver

[bugzilla-daemon@kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=221238

--- Comment #1 from Alfonso GARCIA FREY (alfonso.garcia.frey@gmail.com) ---
Correction to the original description after creating a local test patch:

The original report incorrectly states the driver uses "raw inb()/outb() calls"
and references a battery_hook_register() function. Neither is accurate. The
actual situation:

The lg-laptop driver calls ACPI methods WMAB, WMBB, and GGOV via
acpi_evaluate_object(). These firmware-defined methods internally access the EC
through I/O ports shared with the i8042 keyboard controller, without
coordination with the kernel's i8042 driver. This causes the race condition
between ACPI method execution and atkbd interrupt handling, producing the
spurious ACKs and key drops.

The proposed fix remains the same — wrap acpi_evaluate_object() calls with
i8042_lock_chip() / i8042_unlock_chip() — but the reason is to serialize ACPI
method execution (which internally touches i8042 ports) with the i8042
interrupt handler, not to protect direct port I/O in the driver itself.

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