punktfunk/packaging/windows/drivers/pf-dualsense/README.md

pf-dualsense — virtual DualSense UMDF2 HID minidriver

A self-authored Rust UMDF2 HID minidriver that presents a virtual Sony DualSense (VID 054C / PID 0CE6) to Windows, so games drive adaptive triggers / lightbar / rumble — capabilities ViGEm structurally cannot deliver. It's how the punktfunk Windows host gives a client's DualSense a near-native feel with no external gamepad dependencies (no ViGEmBus).

Shipping: the driver is one member of the in-tree driver workspace (packaging/windows/drivers/), built from source in CI, and bundled + pnputil-installed by the Windows host installer. The host feeds it over a shared memory channel from crates/punktfunk-host/src/inject/dualsense_windows.rs. The same UMDF driver also serves the DualShock 4 identity per a device_type byte the host stamps.

This README captures the driver-authoring lore — the bugs and the signing recipe that make a self-signed UMDF HID driver actually load. The authoritative build/sign/package flow (CI + Inno Setup) lives in the Windows host packaging README.

Build workspace

This crate builds as a member of the packaging/windows/drivers/ workspace, which uses the published crates.io wdk/wdk-sys/wdk-build (0.4/0.5) — not the old dev-box windows-drivers-rs path-deps. It's a separate cargo workspace from the main tree because driver crates are cdylibs built with the WDK toolchain on Windows only; it path-deps the shared ABI crate crates/pf-driver-proto.

Build / sign / install recipe (the one that actually loads)

Prereqs on the Windows box: WDK 26100, LLVM (the current default; bindgen 0.72 builds on clang 22), Rust MSVC. Built as a member of the packaging/windows/drivers/ workspace (plain cargo build, no cargo-make). A self-signed CodeSigning cert in CurrentUser\My + LocalMachine\Root + TrustedPublisher.

Every build needs:

$env:LIBCLANG_PATH = 'C:\Program Files\LLVM\bin'
$env:Version_Number = '10.0.26100.0'   # else wdk-build picks 10.0.28000.0 (no km/crt) and bindgen fails

Then, in the example dir:

cargo make                              # -> target\debug\pf_dualsense_package\ (.inf/.cat/.dll)

# *** CRITICAL: clear the PE FORCE_INTEGRITY bit ***
# windows-drivers-rs links the DLL with /INTEGRITYCHECK, which forces a CI-trusted page-hash
# signature a self-signed cert cannot satisfy (CodeIntegrity 3004 "hash not found" /
# 3089 VerificationError 7). SudoVDA.dll has this bit OFF. Clear bit 0x80 at PE-header offset +0x5e:
$f = 'target\debug\pf_dualsense_package\pf_dualsense.dll'
$b = [IO.File]::ReadAllBytes($f); $pe = [BitConverter]::ToInt32($b,0x3c); $off = $pe + 0x5e
$dc = [BitConverter]::ToUInt16($b,$off); $bb = [BitConverter]::GetBytes([uint16]($dc -band 0xFF7F))
$b[$off]=$bb[0]; $b[$off+1]=$bb[1]; [IO.File]::WriteAllBytes($f,$b)

signtool sign /fd SHA256 /sha1 <cert-thumbprint> $f
Remove-Item target\debug\pf_dualsense_package\pf_dualsense.cat
Inf2Cat /driver:target\debug\pf_dualsense_package /os:10_x64
signtool sign /fd SHA256 /sha1 <cert-thumbprint> target\debug\pf_dualsense_package\pf_dualsense.cat

pnputil /add-driver target\debug\pf_dualsense_package\pf_dualsense.inf /install
devgen /add /hardwareid "root\pf_dualsense"     # creates the (transient, SWD) device node

devgen is at ...\Windows Kits\10\Tools\10.0.26100.0\x64\devgen.exe. SWD devgen devices clear on reboot (recreate after each boot). TODO: drop the post-build PE patch by stopping wdk-build emitting /INTEGRITYCHECK.

The three bugs that made it work (porting a WDK C sample to Rust)

WDF_*_CONFIG_INIT / WDF_OBJECT_ATTRIBUTES_INIT macros set non-zero defaults — mem::zeroed() silently breaks them:

1. FORCE_INTEGRITY (above) — the load wall.
2. Timer ExecutionLevel — zeroed = Invalid → WdfTimerCreate 0xC0200209. Set ExecutionLevel/SynchronizationScope = InheritFromParent + AutomaticSerialization = TRUE (the working vhidmini2 shape).
3. Queue Settings.Parallel.NumberOfPresentedRequests — zeroed = 0 → a parallel queue presents zero requests → EvtIoDeviceControl never fires → no HID handshake → ~5 s timeout → CM_PROB_FAILED_START. Set to u32::MAX.

Notes

• Multi-pad works via UmdfHostProcessSharing=ProcessSharingDisabled — each pad gets its own WUDFHost (so the per-instance statics don't collide), and the driver reads its pad index from the device Location (WdfDeviceAllocAndQueryProperty) to map its own *-shm-<index> channel.
• Port of the WDK vhidmini2 UMDF2 sample; the DualSense identity + 273-byte descriptor + feature blobs 0x05/0x09/0x20 come from crates/punktfunk-host/src/inject/dualsense.rs.