From de771ec93ce375ecafd2761c9fb92d4faf40d68a Mon Sep 17 00:00:00 2001
From: wendlinga <wendling.andrew@gmail.com>
Date: Wed, 15 Apr 2026 12:25:26 -0700
Subject: [PATCH] Fix Metal crash on Intel Mac AMD GPU (missing
 setArgumentBuffer)

On macOS 11+, all GPUs are reported as Tier 2 for argument buffers. Intel Mac
AMD GPUs (AMDMTLBronzeDriver) do not support Metal3 direct buffer addresses.
The constructor skips setArgumentBuffer() when useArgumentBuffersTier2=true,
leaving the encoder without a backing buffer. Calling setBuffer() on it then
causes a SIGSEGV inside AMDMTLBronzeDriver.

Fix: call setArgumentBuffer() before setBuffer() in the non-direct-address path.
---
 plume_metal.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/plume_metal.cpp b/plume_metal.cpp
index fd27894..69d7ee8 100644
--- a/plume_metal.cpp
+++ b/plume_metal.cpp
@@ -1847,6 +1847,12 @@ namespace plume {
                         uint64_t gpuAddress = nativeBuffer->gpuAddress() + bufferDescriptor->offset;
                         *reinterpret_cast<uint64_t*>(bufferPtr + argumentOffset) = gpuAddress;
                     } else {
+                        // On Tier 2 devices without direct buffer addresses (e.g. Intel Mac AMD on macOS 11+),
+                        // the argument encoder's backing buffer must be set before encoding arguments.
+                        // macOS 11+ reports all GPUs as Tier 2, but Intel AMD GPUs skip setArgumentBuffer
+                        // in the constructor because useArgumentBuffersTier2 is true. Without this call
+                        // the encoder has no backing buffer, causing a SIGSEGV in AMDMTLBronzeDriver.
+                        argumentBuffer.argumentEncoder->setArgumentBuffer(argumentBuffer.mtl, argumentBuffer.offset);
                         argumentBuffer.argumentEncoder->setBuffer(nativeBuffer, bufferDescriptor->offset, argumentIndex);
                     }
                     nativeBuffer->retain();