fix: disable wakeup_on_write by default to prevent HID lockup on host reboot

[7tg]

Summary

• Disable wakeup_on_write by default in both S03usbdev (regular mode) and S03usbhid (HID-only mode)
• Invert the opt-out flag (/boot/usb.notwakeup) to an opt-in flag (/boot/usb.wakeup) so the safe default requires no user action

Problem

When wakeup_on_write is enabled (current default), every HID write (keyboard/mouse input) triggers a USB remote wakeup signal. When the host PC is restarting, in BIOS/UEFI, or has suspended USB:

1. The DWC2 controller spams wakeup signals that the host rejects:

   dwc2 4340000.usb: wakeup: signalling skipped: is not allowed by host
   configfs-gadget gadget: usb_gadget_wakeup
   

2. This causes USB endpoint transfer timeouts:

   dwc2 4340000.usb: dwc2_hsotg_ep_stop_xfr: timeout GINTSTS.GOUTNAKEFF
   dwc2 4340000.usb: dwc2_hsotg_ep_stop_xfr: timeout DOEPCTL.EPDisable
   

3. The USB gadget gets stuck — keyboard and mouse become permanently unresponsive
4. In severe cases (Rebooting PC causes USB errors (keyboard + mouse + drive) #220), this causes a kernel NULL pointer dereference crash

This is a widespread issue affecting NanoKVM Full, Lite, and PCIe variants across many host systems.

Root Cause

The wakeup_on_write feature attempts USB remote wakeup signalling on every HID report write. Many host USB controllers do not allow remote wakeup (especially during boot/BIOS, restart, or on certain chipsets like Intel N100/N305). The failed wakeup attempts corrupt the DWC2 endpoint state machine, making recovery impossible without a full PHY restart.

Fix

USB HID devices do not require remote wakeup to function — the host re-enumerates the gadget naturally after reboot. The fix simply inverts the default:

• Before: wakeup_on_write=1 unless /boot/usb.notwakeup exists (unsafe default)
• After: wakeup_on_write=0 unless /boot/usb.wakeup exists (safe default)

Users who specifically need USB remote wakeup can opt in by creating /boot/usb.wakeup.

Testing

Tested on NanoKVM PCIe (firmware 2.3.1) connected to a desktop PC:

• Host reboot no longer causes HID lockup
• Keyboard and mouse remain functional through host restart cycle
• No more wakeup: signalling skipped or ep_stop_xfr: timeout errors in dmesg

Related Issues

Fixes #220 — Rebooting PC causes USB errors (keyboard + mouse + drive) + kernel crash
Fixes #302 — HID stops working
Fixes #383 — USB HID stops working after 10-60s (mouse + keyboard)
Fixes #544 — HID not working in BIOS
Fixes #656 — Keyboard and mouse not working on PCIe KVM