### System details

ASUS laptop with hybrid GPU (Intel iGPU + NVIDIA dGPU), Omarchy on kernel 6.19.10-arch1-1, Hyprland, supergfxctl in Hybrid mode.

### What's wrong?

Closing the laptop lid triggers suspend, but the system crashes or enters a broken state. On the following boot, the journal is full of NVIDIA assertion failures:

```
NVRM: GPU0 nvAssertOkFailedNoLog: Assertion failed: Generic Error: Invalid state [NV_ERR_INVALID_STATE] (0x00000040)
  returned from mmuWalkUnmap(userCtx.pGpuState->pWalk, vaLo, vaHi) @ gpu_vaspace.c:2084
```

This repeats dozens of times in the previous boot's kernel log (`journalctl -b -1 -k`).

### Root cause

The kernel defaults to **s2idle** (S0ix / Low-power S0 idle) instead of **deep** (S3) sleep:

```
$ cat /sys/power/mem_sleep
[s2idle] deep
```

s2idle keeps power to devices and relies on firmware and drivers to manage their own low-power states. The NVIDIA driver does not handle this reliably in Hybrid mode — it fails to properly save/restore GPU VA space mappings (`mmuWalkUnmap` assertion), leading to a crash or compositor freeze on resume.

The existing `/usr/lib/systemd/system-sleep/nvidia` script handles the resume path (`nvidia-sleep.sh resume`) but doesn't address the fundamental s2idle incompatibility.

Additionally, the `10-nvidia-no-freeze-session.conf` drop-in from `nvidia-utils` disables user session freezing during suspend (`SYSTEMD_SLEEP_FREEZE_USER_SESSIONS=false`), which compounds the issue as Wayland clients continue running while the GPU is being suspended — related to #4891.

### Note on `force-igpu` sleep script

The `force-igpu` script in `default/systemd/system-sleep/` is designed for **Integrated** mode only (installed by `omarchy-toggle-hybrid-gpu` when switching to Integrated, removed when switching to Hybrid). It should not be manually installed for Hybrid mode — it would forcibly switch the GPU to Integrated after every wake.

### Possible fix

Adding `mem_sleep_default=deep` to kernel parameters forces S3 deep sleep instead of s2idle, which gives the NVIDIA driver a clean power-off/power-on cycle. This is more reliable for hybrid GPU laptops.

For systemd-boot:
```bash
# Add to kernel cmdline in boot entry
mem_sleep_default=deep
```

After applying:
```
$ cat /sys/power/mem_sleep
s2idle [deep]
```

Omarchy could detect NVIDIA hybrid GPU setups and default to deep sleep, or document this as a recommended configuration for affected hardware.