add a realtime scheduler class and priority-inheritance mutexes with timeouts and abandonment, add an HDA audio driver and a SYS_AUDIO_* syscall family, flesh out kernel32 with Win32 threads, events, mutexes, critical sections, and condition variables, add SYS_RESUME_THREAD for suspended thread creation, add KeInitializeMemoryTypes to reprogram MTRRs and install a canonical PAT for WB/WC/UC control, rework the display pipeline with a pitched present path and console output flush, bring back disk.vhd with mtools since vvfat fucking sucks, harden AHCI with serialized cache flush, USB mass storage with SCSI sense-data decoding, and xHCI with cleaner DMA teardown, fix the last stray for(;;) in HalStopProcessor to while(true), pile on smoke tests for audio, win32 sync primitives, and thread suspend, implement AHCI timeout, kill readahead since it was desperetaly trying to murder me, fix doom sound x2.

code/public/ntlite/ddk/audio.h

@@ -0,0 +1,105 @@
+// Public nt-lite kernel-audio provider declarations.
+
+#pragma once
+
+#include <stddef.h>
+#include <stdint.h>
+#include <ntlite/status.h>
+
+struct DEVICE_OBJECT;
+typedef struct IO_AUDIO_ENDPOINT IO_AUDIO_ENDPOINT;
+
+// Identifies one logical render destination rather than one codec pin.
+typedef enum IO_AUDIO_ENDPOINT_KIND {
+    IoAudioEndpointLineOut = 1,
+    IoAudioEndpointSpeakerHeadphone,
+    IoAudioEndpointOtherAnalog
+} IO_AUDIO_ENDPOINT_KIND;
+
+// Identifies the canonical interleaved PCM sample representation.
+typedef enum IO_AUDIO_SAMPLE_FORMAT {
+    IoAudioSampleS16 = 1
+} IO_AUDIO_SAMPLE_FORMAT;
+
+// Describes interleaved PCM frames.
+typedef struct IO_AUDIO_FORMAT {
+    uint32_t SampleRate;
+    uint16_t ChannelCount;
+    uint16_t SampleFormat;
+} IO_AUDIO_FORMAT;
+
+#define IO_AUDIO_ENDPOINT_CAP_JACK_SENSE     0x00000001u
+#define IO_AUDIO_ENDPOINT_CAP_HARDWARE_GAIN  0x00000002u
+#define IO_AUDIO_ENDPOINT_CAP_VALID_MASK     0x00000003u
+
+// Bounds provider-advertised hardware gain ranges in millidecibels.
+#define IO_AUDIO_HARDWARE_GAIN_LIMIT_MILLIDB 200000
+
+// Distinguishes orderly teardown from surprise removal where registers may no longer be accessible.
+typedef enum IO_AUDIO_REMOVAL_MODE {
+    IoAudioOrderlyRemoval = 1,
+    IoAudioSurpriseRemoval
+} IO_AUDIO_REMOVAL_MODE;
+
+#define IO_AUDIO_FAILURE_HARDWARE_INACCESSIBLE 0x00000001u
+#define IO_AUDIO_FAILURE_VALID_MASK             0x00000001u
+
+// Provider operations are invoked only at PASSIVE_LEVEL by the endpoint mixer thread.
+typedef struct IO_AUDIO_PROVIDER_OPERATIONS {
+    // Starts DMA only after the ring contains at least two prepared periods.
+    // Failure must leave the provider stopped; Stop may still be called for partial-start cleanup.
+    KSTATUS (*Start)(void* providerContext);
+    // Stops DMA before unregister permits provider storage to be released.
+    void (*Stop)(void* providerContext);
+    // Applies endpoint gain and mute only with IO_AUDIO_ENDPOINT_CAP_HARDWARE_GAIN.
+    KSTATUS (*SetGain)(void* providerContext, int32_t gainMilliDb, uint8_t muted);
+} IO_AUDIO_PROVIDER_OPERATIONS;
+
+// Registers one fixed-format render ring owned by a hardware provider.
+// The provider must keep DMA stopped and the physical output muted until Start is called.
+typedef struct IO_AUDIO_ENDPOINT_REGISTRATION {
+    struct DEVICE_OBJECT* Device;
+    IO_AUDIO_ENDPOINT_KIND Kind;
+    uint32_t Capabilities;
+    uint8_t InitiallyAvailable;
+    void* ProviderContext;
+    IO_AUDIO_PROVIDER_OPERATIONS Operations;
+    void* PeriodBuffer;
+    size_t PeriodBufferBytes;
+    uint32_t PeriodCount;
+    uint32_t FramesPerPeriod;
+    size_t PeriodStrideBytes;
+    IO_AUDIO_FORMAT HardwareFormat;
+    // Gain fields must be zero unless IO_AUDIO_ENDPOINT_CAP_HARDWARE_GAIN is present.
+    int32_t HardwareGainMinimumMilliDb;
+    int32_t HardwareGainMaximumMilliDb;
+    uint32_t HardwareGainStepMilliDb;
+} IO_AUDIO_ENDPOINT_REGISTRATION;
+
+// Driver-visible services for registering and advancing kernel audio endpoints.
+typedef struct NTL_DDK_AUDIO {
+    // Registers one endpoint and returns a provider-owned reference valid until unregister returns.
+    KSTATUS (*RegisterEndpoint)(const IO_AUDIO_ENDPOINT_REGISTRATION* registration,
+                                IO_AUDIO_ENDPOINT** outEndpoint);
+
+    // Stops the endpoint, removes it from enumeration, and consumes the provider-owned reference.
+    void (*UnregisterEndpoint)(IO_AUDIO_ENDPOINT* endpoint, IO_AUDIO_REMOVAL_MODE mode);
+
+    // Reports one completed hardware period from ISR/DPC completion processing.
+    // presentedFrames, hardwarePositionFrames, and interruptCount must be monotonic for the
+    // endpoint lifetime. timestampTicks uses the DDK monotonic microsecond source.
+    void (*NotifyPeriod)(IO_AUDIO_ENDPOINT* endpoint,
+                         uint32_t completedPeriodIndex,
+                         uint64_t presentedFrames,
+                         uint64_t hardwarePositionFrames,
+                         uint64_t interruptCount,
+                         uint64_t timestampTicks);
+
+    // Updates jack-derived endpoint availability without changing endpoint identity.
+    void (*SetEndpointAvailable)(IO_AUDIO_ENDPOINT* endpoint, uint8_t available);
+
+    // Fails an endpoint and wakes every stream owner.
+    void (*ReportEndpointFailure)(IO_AUDIO_ENDPOINT* endpoint,
+                                  KSTATUS status,
+                                  uint32_t flags);
+} NTL_DDK_AUDIO;