From ded446b34c0cd803a0122446b848619adbb458cf Mon Sep 17 00:00:00 2001
From: lhez <lih@qti.qualcomm.com>
Date: Thu, 26 Mar 2026 08:52:21 -0700
Subject: [PATCH] opencl: allow large buffer for adreno (#20997)

---
 ggml/src/ggml-opencl/ggml-opencl.cpp | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/ggml/src/ggml-opencl/ggml-opencl.cpp b/ggml/src/ggml-opencl/ggml-opencl.cpp
index 4dddcd82cf..c40e1f2d39 100644
--- a/ggml/src/ggml-opencl/ggml-opencl.cpp
+++ b/ggml/src/ggml-opencl/ggml-opencl.cpp
@@ -394,6 +394,9 @@ struct ggml_backend_opencl_context {
     bool fp16_support;
     bool has_vector_subgroup_broadcast;
     bool disable_fusion;
+
+    bool adreno_has_large_buffer;
+    bool adreno_use_large_buffer;
     ggml_cl_compiler_version adreno_cl_compiler_version;
 
     int adreno_wave_size;
@@ -787,6 +790,10 @@ static void load_cl_kernels(ggml_backend_opencl_context *backend_ctx, ggml_cl_ve
                                " -cl-mad-enable -cl-unsafe-math-optimizations"
                                " -cl-finite-math-only -cl-fast-relaxed-math";
 
+    if (backend_ctx->adreno_use_large_buffer) {
+        compile_opts += " -qcom-enable-large-buffer ";
+    }
+
     GGML_LOG_INFO("ggml_opencl: loading OpenCL kernels");
 
     // add
@@ -3020,6 +3027,8 @@ static ggml_backend_opencl_context * ggml_cl2_init(ggml_backend_dev_t dev) {
     // Check if ext_buffer contains cl_khr_fp16
     backend_ctx->fp16_support = strstr(ext_buffer, "cl_khr_fp16") != NULL;
     GGML_LOG_INFO("ggml_opencl: device FP16 support: %s\n", backend_ctx->fp16_support ? "true" : "false");
+    // check Adreno large buffer support
+    backend_ctx->adreno_has_large_buffer = strstr(ext_buffer, "cl_qcom_large_buffer") != NULL;
 
     // fp16 is required
     if (!backend_ctx->fp16_support) {
@@ -3086,6 +3095,18 @@ static ggml_backend_opencl_context * ggml_cl2_init(ggml_backend_dev_t dev) {
     GGML_LOG_INFO("ggml_opencl: using kernels optimized for Adreno (GGML_OPENCL_USE_ADRENO_KERNELS)\n");
 #endif // GGML_OPENCL_USE_ADRENO_KERNELS
 
+    // determine whether to use large buffer for Adreno
+    backend_ctx->adreno_use_large_buffer = getenv("GGML_OPENCL_ADRENO_USE_LARGE_BUFFER") != nullptr &&
+                                           backend_ctx->gpu_family == GPU_FAMILY::ADRENO;
+    if (backend_ctx->adreno_use_large_buffer) {
+        if (!backend_ctx->adreno_has_large_buffer) {
+            GGML_LOG_INFO("ggml_opencl: Adreno large buffer requested but not supported by driver, will use regular buffer\n");
+            backend_ctx->adreno_use_large_buffer = false;
+        } else {
+            GGML_LOG_INFO("ggml_opencl: Adreno large buffer enabled\n");
+        }
+    }
+
     cl_int err;
 
     // A local ref of cl_context for convenience
@@ -5660,6 +5681,11 @@ static ggml_backend_buffer_t ggml_backend_opencl_buffer_type_alloc_buffer(ggml_b
 
     cl_int err;
     cl_mem mem = clCreateBuffer(backend_ctx->context, CL_MEM_READ_WRITE, size, NULL, &err);
+    if (err != CL_SUCCESS && backend_ctx->adreno_use_large_buffer) {
+        cl_mem_properties props[] = { 0x41A6 /* CL_LARGE_BUFFER_QCOM */, 1, 0 };
+        mem = clCreateBufferWithProperties(backend_ctx->context, props, CL_MEM_READ_WRITE, size, NULL, &err);
+    }
+
     if (err != CL_SUCCESS) {
         GGML_LOG_INFO("%s: failed to allocate %.2f MiB\n", __func__, size / 1024.0 / 1024.0);
         return nullptr;