feat(windows-drivers): STEP 7 — HDR/FP16 (validated on-glass: Mac connects WITH HDR)

The pf-vdisplay driver now advertises HDR/FP16 and the full glass-to-glass HDR path works
end-to-end — validated LIVE: the Mac client connected to the .173 host WITH HDR (display_hdr=true,
FP16 ring -> NVENC P010). The STEP-3 assumption that FP16 needs a higher UmdfExtensions was WRONG:
IddCx0102 + CAN_PROCESS_FP16 + the *2 DDIs works (the oracle proved it; confirmed on-glass
IddCxAdapterInitAsync -> 0x0 WITH the FP16 cap set). Driver-only change — the host FP16-ring ->
NVENC-P010 path and the HDR EDID were already in place.

- adapter.rs: caps.Flags = IDDCX_ADAPTER_FLAGS_CAN_PROCESS_FP16.
- entry.rs: register the 6 *2/HDR callbacks (ParseMonitorDescription2, MonitorQueryTargetModes2,
  AdapterCommitModes2, AdapterQueryTargetInfo, MonitorSetDefaultHdrMetaData, MonitorSetGammaRamp)
  ALONGSIDE the v1 set (matching the oracle — CAN_PROCESS_FP16 OBLIGATES the *2 DDIs or the
  framework rejects the adapter at init; STEP 3 rejected FP16 only because they weren't registered).
- callbacks.rs: parse_monitor_description2 + monitor_query_modes2 now fill IDDCX_MONITOR_MODE2 /
  IDDCX_TARGET_MODE2 with BitsPerComponent (8|10 bpc RGB); query_target_info already reports
  IDDCX_TARGET_CAPS_HIGH_COLOR_SPACE; set_default_hdr_metadata + set_gamma_ramp accept (the gamma
  one is mandatory under FP16).
- monitor.rs: wire_bits() (Rgb 8|10, no YCbCr) + target_mode2().
- EDID + INF UNCHANGED (the EDID already carries the CTA-861.3 BT.2020 + ST.2084/PQ block; the INF
  stays UmdfExtensions=IddCx0102).

Built via the ultracode flow (STEP-7 map workflow -> agent-implement -> box build [driver green] ->
deploy -> on-glass HDR). OPERATIONAL NOTE: do NOT Disable/Enable the IddCx devnode to reload it —
that leaves the adapter STOPPED in the persisted WUDFHost process (ADAPTER OnceLock survives), so
monitor-create then fails with 0xc00002b6 (INDIRECT_DISPLAY_DEVICE_STOPPED). Kill the pf_vdisplay
WUDFHost process (or reboot) for a clean adapter re-init.

This completes the pf-vdisplay rewrite STEP 0-7, all on-glass validated (loads, adapter inits,
monitor appears, swap-chain drain, IDD-push frames at ~235fps, and HDR). Remaining: STEP 8 (unsafe-
reduction + delete the old vdisplay-driver tree + the vendored SudoVDA driver + unbundle from the
installer = the SudoVDA drop).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packaging/windows/drivers/pf-vdisplay/src/callbacks.rs

@@ -81,11 +81,53 @@ pub unsafe extern "C" fn parse_monitor_description(
     STATUS_SUCCESS
 }
 
-/// HDR (`*2`) mode list — writes `IDDCX_MONITOR_MODE2` (+BitsPerComponent). Mandatory under FP16.
+/// HDR (`*2`) mode list — writes `IDDCX_MONITOR_MODE2` (+BitsPerComponent). Mandatory under FP16. Mirrors
+/// the v1 `parse_monitor_description` exactly (EDID-serial lookup → count-then-fill, same
+/// BUFFER_TOO_SMALL/SUCCESS logic), but emits `IDDCX_MONITOR_MODE2` with the per-mode wire bit-depth so the
+/// OS offers HDR10 modes. `IDARG_OUT_PARSEMONITORDESCRIPTION` is the SAME out struct as v1 (shared by the C
+/// header); only the in-args / mode struct are the `*2` variants.
 pub unsafe extern "C" fn parse_monitor_description2(
-    _p_in: *const iddcx::IDARG_IN_PARSEMONITORDESCRIPTION2,
-    _p_out: *mut iddcx::IDARG_OUT_PARSEMONITORDESCRIPTION,
+    p_in: *const iddcx::IDARG_IN_PARSEMONITORDESCRIPTION2,
+    p_out: *mut iddcx::IDARG_OUT_PARSEMONITORDESCRIPTION,
 ) -> NTSTATUS {
+    // SAFETY: framework-provided in/out args, valid for the call.
+    let in_args = unsafe { &*p_in };
+    let out_args = unsafe { &mut *p_out };
+    // SAFETY: the framework supplies a valid EDID buffer of `DataSize` bytes.
+    let edid = unsafe {
+        core::slice::from_raw_parts(
+            in_args.MonitorDescription.pData.cast::<u8>(),
+            in_args.MonitorDescription.DataSize as usize,
+        )
+    };
+    let Ok(id) = crate::edid::Edid::get_serial(edid) else {
+        return STATUS_INVALID_PARAMETER;
+    };
+    let Some(modes) = crate::monitor::modes_for_id(id) else {
+        return STATUS_NOT_FOUND;
+    };
+    let count = crate::monitor::flatten(&modes).count() as u32;
+    out_args.MonitorModeBufferOutputCount = count;
+    if in_args.MonitorModeBufferInputCount < count {
+        // A zero input count is a count-only probe (success); a non-zero too-small buffer is an error.
+        return if in_args.MonitorModeBufferInputCount > 0 {
+            STATUS_BUFFER_TOO_SMALL
+        } else {
+            STATUS_SUCCESS
+        };
+    }
+    // SAFETY: `pMonitorModes` points to >= `count` IDDCX_MONITOR_MODE2 entries (validated above).
+    let out = unsafe { core::slice::from_raw_parts_mut(in_args.pMonitorModes, count as usize) };
+    for (item, slot) in crate::monitor::flatten(&modes).zip(out.iter_mut()) {
+        let mut mode: iddcx::IDDCX_MONITOR_MODE2 = unsafe { core::mem::zeroed() };
+        mode.Size = core::mem::size_of::<iddcx::IDDCX_MONITOR_MODE2>() as u32;
+        mode.Origin = iddcx::IDDCX_MONITOR_MODE_ORIGIN::IDDCX_MONITOR_MODE_ORIGIN_MONITORDESCRIPTOR;
+        mode.MonitorVideoSignalInfo =
+            crate::monitor::display_info(item.width, item.height, item.refresh_rate);
+        mode.BitsPerComponent = crate::monitor::wire_bits();
+        *slot = mode;
+    }
+    out_args.PreferredMonitorModeIdx = 0;
     STATUS_SUCCESS
 }
 
@@ -122,12 +164,30 @@ pub unsafe extern "C" fn monitor_query_modes(
     STATUS_SUCCESS
 }
 
-/// HDR (`*2`) target modes — writes `IDDCX_TARGET_MODE2`. Mandatory under FP16.
+/// HDR (`*2`) target modes — writes `IDDCX_TARGET_MODE2`. Mandatory under FP16. Mirrors the v1
+/// `monitor_query_modes` exactly (pointer-match the monitor → count → fill), but emits `IDDCX_TARGET_MODE2`
+/// (with per-mode wire bit-depth) via `monitor::target_mode2`. `IDARG_OUT_QUERYTARGETMODES` is the SAME out
+/// struct as v1.
 pub unsafe extern "C" fn monitor_query_modes2(
-    _monitor: iddcx::IDDCX_MONITOR,
-    _p_in: *const iddcx::IDARG_IN_QUERYTARGETMODES2,
-    _p_out: *mut iddcx::IDARG_OUT_QUERYTARGETMODES,
+    monitor: iddcx::IDDCX_MONITOR,
+    p_in: *const iddcx::IDARG_IN_QUERYTARGETMODES2,
+    p_out: *mut iddcx::IDARG_OUT_QUERYTARGETMODES,
 ) -> NTSTATUS {
+    // SAFETY: framework-provided in/out args, valid for the call.
+    let in_args = unsafe { &*p_in };
+    let out_args = unsafe { &mut *p_out };
+    let Some(modes) = crate::monitor::modes_for_object(monitor) else {
+        return STATUS_NOT_FOUND;
+    };
+    let count = crate::monitor::flatten(&modes).count() as u32;
+    out_args.TargetModeBufferOutputCount = count;
+    if in_args.TargetModeBufferInputCount >= count {
+        // SAFETY: `pTargetModes` points to >= `count` IDDCX_TARGET_MODE2 entries.
+        let out = unsafe { core::slice::from_raw_parts_mut(in_args.pTargetModes, count as usize) };
+        for (item, slot) in crate::monitor::flatten(&modes).zip(out.iter_mut()) {
+            *slot = crate::monitor::target_mode2(item.width, item.height, item.refresh_rate);
+        }
+    }
     STATUS_SUCCESS
 }