OcMainLib: Added `ResetTrafficClass` to reset TCSEL to T0 on legacy HDA

Changelog.md

@@ -19,6 +19,7 @@ OpenCore Changelog
 - Added `acdtinfo` utility to lookup certain products
 - Fixed `FSBFrequency` calculation with fractional multiplier
 - Fixed showing core count for some AMD CPUs
+- Added `ResetTrafficClass` to reset TCSEL to T0 on legacy HDA
 
 #### v0.6.6
 - Added keyboard and pointer entry scroll support in OpenCanopy

Docs/Configuration.tex

@@ -6142,6 +6142,19 @@ functioning. Feature highlights:
   \emph{Note}: \texttt{Enabled} can be used in separate from \texttt{StartupMute}
   NVRAM variable to avoid conflicts when the firmware is able to play boot chime.
 
+\item
+  \texttt{ResetTrafficClass}\\
+  \textbf{Type}: \texttt{plist\ boolean}\\
+  \textbf{Failsafe}: \texttt{false}\\
+  \textbf{Description}: Set HDA Traffic Class Select Register to \texttt{TC0}.
+
+  AppleHDA kext will function correctly only if \texttt{TCSEL} register is configured
+  to use \texttt{TC0} traffic class. Refer to Intel I/O Controller Hub 9 (ICH9) Family
+  Datasheet (or any other ICH datasheet) for more details about this register.
+
+  \emph{Note}: This option is independent from \texttt{AudioSupport}. If AppleALC is used 
+  it is preferred to use AppleALC \texttt{alctsel} property instead.
+
 \item
   \texttt{SetupDelay}\\
   \textbf{Type}: \texttt{plist\ integer}\\

Docs/Sample.plist

@@ -1086,6 +1086,8 @@
 			<integer>20</integer>
 			<key>PlayChime</key>
 			<string>Auto</string>
+			<key>ResetTrafficClass</key>
+			<false/>
 			<key>SetupDelay</key>
 			<integer>0</integer>
 			<key>VolumeAmplifier</key>

Docs/SampleCustom.plist

@@ -1283,6 +1283,8 @@
 			<integer>20</integer>
 			<key>PlayChime</key>
 			<string>Auto</string>
+			<key>ResetTrafficClass</key>
+			<false/>
 			<key>SetupDelay</key>
 			<integer>0</integer>
 			<key>VolumeAmplifier</key>

Include/Acidanthera/Library/OcConfigurationLib.h

@@ -590,7 +590,8 @@ typedef enum {
   _(BOOLEAN                     , AudioSupport       ,     , FALSE                             , ()) \
   _(UINT8                       , AudioCodec         ,     , 0                                 , ()) \
   _(UINT8                       , AudioOut           ,     , 0                                 , ()) \
-  _(UINT8                       , MinimumVolume      ,     , 0                                 , ())
+  _(UINT8                       , MinimumVolume      ,     , 0                                 , ()) \
+  _(BOOLEAN                     , ResetTrafficClass  ,     , FALSE                             , ())
   OC_DECLARE (OC_UEFI_AUDIO)
 
 ///

Library/OcConfigurationLib/OcConfigurationLib.c

@@ -714,6 +714,7 @@ mUefiAudioSchema[] = {
   OC_SCHEMA_BOOLEAN_IN ("AudioSupport",       OC_GLOBAL_CONFIG, Uefi.Audio.AudioSupport),
   OC_SCHEMA_INTEGER_IN ("MinimumVolume",      OC_GLOBAL_CONFIG, Uefi.Audio.MinimumVolume),
   OC_SCHEMA_STRING_IN  ("PlayChime",          OC_GLOBAL_CONFIG, Uefi.Audio.PlayChime),
+  OC_SCHEMA_BOOLEAN_IN ("ResetTrafficClass",  OC_GLOBAL_CONFIG, Uefi.Audio.ResetTrafficClass),
   OC_SCHEMA_INTEGER_IN ("SetupDelay",         OC_GLOBAL_CONFIG, Uefi.Audio.SetupDelay),
   OC_SCHEMA_INTEGER_IN ("VolumeAmplifier",    OC_GLOBAL_CONFIG, Uefi.Audio.VolumeAmplifier),
 };

Library/OcMainLib/OcMainLib.inf

@@ -51,6 +51,7 @@
   gOcInterfaceProtocolGuid            ## SOMETIMES_CONSUMES
   gEfiSecurityArchProtocolGuid        ## SOMETIMES_CONSUMES
   gEfiSecurity2ArchProtocolGuid       ## SOMETIMES_CONSUMES
+  gEfiPciIoProtocolGuid               ## SOMETIMES_CONSUMES
 
 [LibraryClasses]
   DevicePathLib

Library/OcMainLib/OpenCoreUefiAudio.c

@@ -17,7 +17,9 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #include <Guid/AppleVariable.h>
 #include <Guid/OcVariable.h>
 #include <Guid/GlobalVariable.h>
+#include <IndustryStandard/Pci30.h>
 #include <Protocol/AudioDecode.h>
+#include <Protocol/PciIo.h>
 
 #include <Library/BaseLib.h>
 #include <Library/DebugLib.h>
@@ -469,6 +471,84 @@ OcAudioExitBootServices (
   OcAudio->StopPlayback (OcAudio, TRUE);
 }
 
+STATIC
+VOID
+ResetAudioTrafficClass (
+  VOID
+  )
+{
+  EFI_STATUS           Status;
+  UINTN                HandleCount;
+  EFI_HANDLE           *HandleBuffer;
+  UINTN                Index;
+  EFI_PCI_IO_PROTOCOL  *PciIo;
+  UINT32               ClassCode;
+  UINT8                TrafficClass;
+
+  Status = gBS->LocateHandleBuffer (
+    ByProtocol,
+    &gEfiPciIoProtocolGuid,
+    NULL,
+    &HandleCount,
+    &HandleBuffer
+    );
+
+  if (EFI_ERROR (Status)) {
+    DEBUG ((DEBUG_INFO, "OC: No PCI devices for TCSEL reset - %r\n", Status));
+    return;
+  }
+
+  for (Index = 0; Index < HandleCount; ++Index) {
+    Status = gBS->HandleProtocol (
+      HandleBuffer[Index],
+      &gEfiPciIoProtocolGuid,
+      (VOID **) &PciIo
+      );
+
+    if (EFI_ERROR (Status)) {
+      continue;
+    }
+
+    Status = PciIo->Pci.Read (
+      PciIo,
+      EfiPciIoWidthUint32,
+      OFFSET_OF (PCI_DEVICE_INDEPENDENT_REGION, RevisionID),
+      1,
+      &ClassCode
+      );
+    if (EFI_ERROR (Status)) {
+      continue;
+    }
+
+    ClassCode >>= 16U; ///< Drop revision and minor codes.
+    if (ClassCode == (PCI_CLASS_MEDIA << 8 | PCI_CLASS_MEDIA_AUDIO)
+      || ClassCode == (PCI_CLASS_MEDIA << 8 | 0x3 /* PCI_CLASS_MEDIA_HDA */)) {
+      Status = PciIo->Pci.Read (PciIo, EfiPciIoWidthUint8, 0x44 /* TCSEL */, 1, &TrafficClass);
+      if (EFI_ERROR (Status)) {
+        continue;
+      }
+
+      DEBUG ((
+        DEBUG_INFO,
+        "OC: Discovered audio device at %u/%u with TCSEL %X\n",
+        (UINT32) (Index + 1),
+        (UINT32) HandleCount,
+        TrafficClass
+        ));
+
+      //
+      // Update Traffic Class Select Register to TC0.
+      // This is required for AppleHDA to output audio on some machines.
+      // See Intel I/O Controller Hub 9 (ICH9) Family Datasheet for more details.
+      //
+      if ((TrafficClass & 0x7U) != 0) {
+        TrafficClass &= ~0x7U;
+        PciIo->Pci.Write (PciIo, EfiPciIoWidthUint8, 0x44 /* TCSEL */, 1, &TrafficClass);
+      }
+    }
+  }
+}
+
 VOID
 OcLoadUefiAudioSupport (
   IN OC_STORAGE_CONTEXT  *Storage,
@@ -483,6 +563,10 @@ OcLoadUefiAudioSupport (
   UINT8                            VolumeLevel;
   BOOLEAN                          Muted;
 
+  if (Config->Uefi.Audio.ResetTrafficClass) {
+    ResetAudioTrafficClass ();
+  }
+
   if (!Config->Uefi.Audio.AudioSupport) {
     DEBUG ((DEBUG_INFO, "OC: Requested not to use audio\n"));
     return;