G515: first wake key after LED sleep is dropped (Shift at password prompt)

Information

• Solaar version: 1.1.20
• Distribution: Fedora Linux 44 (KDE Plasma Desktop Edition)
• Kernel version: Linux 7.1.8-200.fc44.x86_64 x86_64 GNU/Linux
• Output of solaar show (G515 / Lightspeed receiver):

solaar version 1.1.20

Lightspeed Receiver
  Device path  : /dev/hidraw3
  USB id       : 046d:C547
  Serial       : 0116F63F
  Has 2 paired device(s) out of a maximum of 2.

  1: G515 LS TKL
     Device path  : /dev/hidraw5
     WPID         : 40B4
     Codename     : G515 LS TKL
     Kind         : keyboard
     Protocol     : HID++ 4.2
     Report Rate : 8ms
     Serial number: 498C9308
     Model ID:      B38940B4C355
     Unit ID:       498C9308
                 1: BL2 19.00.B0010
                 0: MPK 25.00.B0010
     Supports 34 HID++ 2.0 features:
         9: RGB EFFECTS            {8071} V4
            LED Control (saved): True
            LED Control        : True
            Idle Effect (saved): !LEDEffectSetting {ID: 128, intensity: 50}
            Idle Timeout (saved): 1 Minute
            Sleep Timeout (saved): 5 Minutes
        10: PER KEY LIGHTING V2    {8081} V0

• Relevant ~/.config/solaar/config.yaml (G515 entry):

- _NAME: G515 LS TKL
  _modelId: B38940B4C355
  _wpid: 40B4
  rgb_control: true
  rgb_idle_effect: !LEDEffectSetting {ID: 128, intensity: 50}
  rgb_idle_timeout: 60
  rgb_sleep_timeout: 300
  rgb_zone_1: !LEDEffectSetting {ID: 1, color: 0xffffff, intensity: 100, period: 5000}

Describe the bug

When the G515 Lightspeed TKL has gone to sleep (LEDs off after the 5-minute software sleep timeout), if the first wake key is Shift, the keyboard wakes but the system never sees Shift held. The next character is unshifted. Easy to hit at a lock-screen / password prompt whose first letter is capital.

The keyboard itself does wake; only the wake key is missing from HID input. A letter as the wake key just eats one character; Shift is worse because it is typically held into the next key.

This started after the 1.1.20 G515 LED rewrite (#2791 / #3149). rgb_control is Solaar, idle 60s, sleep 300s.

To Reproduce

1. Leave the G515 idle until the LEDs go fully off (default sleep timeout 5 minutes).
2. Press and hold Left Shift, then type a letter.
3. The letter arrives unshifted. Subsequent Shift+letter while the keyboard is awake works normally.

Additional context

Software sleep sent SetRgbPowerMode(3) (0x8071 function 8). On this keyboard that parks the HID key-scan. The wake key produces an onUserActivity notification; Solaar immediately replied with SetRgbPowerMode(1) plus color restore on the same radio as the HID report, so the first key is consumed as a wake event and not reported.

Fix in #3309: blank LEDs in software instead of SetRgbPowerMode(3), disable the firmware sleep timer, skip SetRgbPowerMode on wake, and defer HID++ restore so it does not race the wake-key HID report. Confirmed on this G515 after copying the patched rgb_power.py over 1.1.20.

Related to, but not the same as, #2791 (LED persistence / demo mode).