Merge commit '873e5d8e39feb34a376e0efd01bf3f665dfffeb5' into concedo_experimental

# Conflicts:
#	.github/workflows/build-cmake-pkg.yml
#	.github/workflows/build-cpu.yml
#	.github/workflows/make-release.yml
#	.github/workflows/release.yml
#	.pi/gg/SYSTEM.md
#	CMakeLists.txt
#	cmake/arm64-windows-llvm.cmake
#	docs/backend/ET.md
#	docs/build.md
#	docs/development/HOWTO-add-model.md
#	ggml/CMakeLists.txt
#	ggml/src/CMakeLists.txt
#	ggml/src/ggml-cpu/CMakeLists.txt
#	ggml/src/ggml-cpu/kleidiai/kernels.cpp
#	ggml/src/ggml-cpu/kleidiai/kleidiai.cpp
#	ggml/src/ggml-hexagon/ggml-hexagon.cpp
#	ggml/src/ggml-hexagon/htp/rope-ops.c
#	ggml/src/ggml-opencl/ggml-opencl.cpp
#	ggml/src/ggml-opencl/kernels/mul_mv_q6_k_f32_flat.cl
#	ggml/src/ggml-opencl/kernels/rope.cl
#	ggml/src/ggml-sycl/dmmv.cpp
#	ggml/src/ggml-sycl/dpct/helper.hpp
#	ggml/src/ggml-sycl/element_wise.cpp
#	ggml/src/ggml-sycl/esimd.hpp
#	ggml/src/ggml-sycl/fattn-mkl.cpp
#	ggml/src/ggml-sycl/fattn-onednn.cpp
#	ggml/src/ggml-sycl/ggml-sycl.cpp
#	ggml/src/ggml-sycl/im2col.cpp
#	ggml/src/ggml-sycl/norm.cpp
#	ggml/src/ggml-sycl/rope.cpp
#	ggml/src/ggml-sycl/set_rows.cpp
#	ggml/src/ggml-vulkan/CMakeLists.txt
#	ggml/src/ggml-webgpu/ggml-webgpu.cpp
#	ggml/src/ggml-webgpu/wgsl-shaders/rope.wgsl
#	ggml/src/ggml-zendnn/CMakeLists.txt
#	scripts/make-release-desc.sh
#	scripts/sync-ggml.last
#	tests/test-backend-ops.cpp
#	tests/test-json-schema-to-grammar.cpp
#	tools/cli/README.md
#	tools/server/README.md
#	tools/ui/src/lib/constants/settings.constants.ts
#	tools/ui/src/lib/services/chat.service.ts

tools/mtmd/clip.cpp

@@ -243,14 +243,13 @@ struct clip_ctx {
             throw std::runtime_error("failed to initialize CPU backend");
         }
         if (ctx_params.use_gpu) {
-            auto * backend_name = std::getenv("MTMD_BACKEND_DEVICE");
-            if (backend_name != nullptr) {
-                backend = ggml_backend_init_by_name(backend_name, nullptr);
+            if (ctx_params.device != nullptr) {
+                backend = ggml_backend_dev_init(ctx_params.device, nullptr);
                 if (!backend) {
-                    LOG_WRN("%s: Warning: Failed to initialize \"%s\" backend, falling back to default GPU backend\n", __func__, backend_name);
+                    throw std::runtime_error(string_format("%s: failed to initialize \"%s\" backend\n",
+                                                           __func__, ggml_backend_dev_name(ctx_params.device)));
                 }
-            }
-            if (!backend) {
+            } else {
                 backend = ggml_backend_init_by_type(GGML_BACKEND_DEVICE_TYPE_GPU, nullptr);
                 backend = backend ? backend : ggml_backend_init_by_type(GGML_BACKEND_DEVICE_TYPE_IGPU, nullptr);
             }