HID: apple: preserve keyboard backlight across T2 resume

The T2 virtual USB host controller re-enumerates the internal keyboard
after system resume. The butterfly keyboard backlight currently uses
LED_CORE_SUSPENDRESUME, so the LED core sends a blocking request to the
old HID device while it is disappearing. That request fails with -ENODEV
and the newly probed device starts with its backlight off.

To fix this, we cache the requested brightness when the old HID device is
removed and restore it when the replacement is probed. We let
re-enumeration handle restoration instead of issuing a request through the
stale device.

Fixes: 1f95a6cd5ad7 ("HID: apple: ensure the keyboard backlight is off if suspending")
Cc: stable@vger.kernel.org
Signed-off-by: Andre Eikmeyer <dev@deq.rocks>
Signed-off-by: Jiri Kosina <jkosina@suse.com>

0 files changed, 0 insertions, 0 deletions