macOS/ARM: Allow populating GPU based on AGXAccelerator

src/gpu_info_util/SystemInfo_macos.mm

@@ -77,40 +77,64 @@ bool GetEntryProperty(io_registry_entry_t entry, CFStringRef name, uint32_t *val
     return true;
 }
 
-// Gathers the vendor and device IDs for the PCI GPUs
-bool GetPCIDevices(std::vector<GPUDeviceInfo> *devices)
+// Gathers the vendor and device IDs for GPUs listed in the IORegistry.
+void GetIORegistryDevices(std::vector<GPUDeviceInfo> *devices)
 {
+    constexpr uint32_t kNumServices         = 2;
+    const char *kServiceNames[kNumServices] = {"IOPCIDevice", "AGXAccelerator"};
+    const bool kServiceIsVGA[kNumServices]  = {true, false};
+    for (uint32_t i = 0; i < kNumServices; ++i)
+    {
         // matchDictionary will be consumed by IOServiceGetMatchingServices, no need to release it.
-    CFMutableDictionaryRef matchDictionary = IOServiceMatching("IOPCIDevice");
+        CFMutableDictionaryRef matchDictionary = IOServiceMatching(kServiceNames[i]);
 
         io_iterator_t entryIterator;
         if (IOServiceGetMatchingServices(kIOMasterPortDefault, matchDictionary, &entryIterator) !=
             kIOReturnSuccess)
         {
-        return false;
+            continue;
         }
 
         io_registry_entry_t entry = IO_OBJECT_NULL;
-
         while ((entry = IOIteratorNext(entryIterator)) != IO_OBJECT_NULL)
         {
             constexpr uint32_t kClassCodeDisplayVGA = 0x30000;
             uint32_t classCode;
             GPUDeviceInfo info;
 
-        if (GetEntryProperty(entry, CFSTR("class-code"), &classCode) &&
-            classCode == kClassCodeDisplayVGA &&
-            GetEntryProperty(entry, CFSTR("vendor-id"), &info.vendorId) &&
-            GetEntryProperty(entry, CFSTR("device-id"), &info.deviceId))
+            // AGXAccelerator entries only provide a vendor ID.
+            if (!GetEntryProperty(entry, CFSTR("vendor-id"), &info.vendorId))
             {
-            devices->push_back(info);
+                continue;
             }
 
+            if (kServiceIsVGA[i])
+            {
+                if (!GetEntryProperty(entry, CFSTR("class-code"), &classCode))
+                {
+                    continue;
+                }
+                if (classCode != kClassCodeDisplayVGA)
+                {
+                    continue;
+                }
+                if (!GetEntryProperty(entry, CFSTR("device-id"), &info.deviceId))
+                {
+                    continue;
+                }
+            }
+
+            devices->push_back(info);
             IOObjectRelease(entry);
         }
         IOObjectRelease(entryIterator);
 
-    return true;
+        // If any devices have been populated by IOPCIDevice, do not continue to AGXAccelerator.
+        if (!devices->empty())
+        {
+            break;
+        }
+    }
 }
 
 void SetActiveGPUIndex(SystemInfo *info)
@@ -217,11 +241,7 @@ bool GetSystemInfo(SystemInfo *info)
         info->machineModelVersion = std::to_string(major) + "." + std::to_string(minor);
     }
 
-    if (!GetPCIDevices(&(info->gpus)))
-    {
-        return false;
-    }
-
+    GetIORegistryDevices(&info->gpus);
     if (info->gpus.empty())
     {
         return false;