Confirmed in-person in Paris; the code is polling /proc/acpi/sony/fn_key for a 16-bit mask that corresponds to the hotkey-pressed and this needs turning into an evdev event.
The workaround for the brightness on these laptops is because the BIOS always replies that the brightness is at level '7'; however the hardware responds correctly when programmed with other values so a local copy is kept of the display brightness, rather than querying the ACPI routine.
Confirmed in-person in Paris; the code is polling /proc/acpi/ sony/fn_ key for a 16-bit mask that corresponds to the hotkey-pressed and this needs turning into an evdev event.
The workaround for the brightness on these laptops is because the BIOS always replies that the brightness is at level '7'; however the hardware responds correctly when programmed with other values so a local copy is kept of the display brightness, rather than querying the ACPI routine.