From 0c17efafa3594f8008ee15dd503a073e12ce48a7 Mon Sep 17 00:00:00 2001
From: Nirbheek Chauhan <nirbheek@centricular.com>
Date: Mon, 2 Dec 2024 17:12:00 +0530
Subject: [PATCH] meson: Improve NVMM CUDA detection

1. Add some comments explaining what headers and libs are expected on
   what systems
2. Only look in default incdirs if no incdir is specified
3. Require libnvbufsurface.so on Jetson when cuda-nvmm=enabled
4. Require libatomic on Jetson when cuda-nvmm=enabled

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/8021>
---
 .../gst-libs/gst/cuda/meson.build             | 69 +++++++++++--------
 1 file changed, 39 insertions(+), 30 deletions(-)

diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/cuda/meson.build b/subprojects/gst-plugins-bad/gst-libs/gst/cuda/meson.build
index 7bf0b320a1..8bd6b58352 100644
--- a/subprojects/gst-plugins-bad/gst-libs/gst/cuda/meson.build
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/cuda/meson.build
@@ -40,8 +40,8 @@ if host_system not in ['windows', 'linux']
 endif
 
 # Linux ARM would need -latomic for std::atomic<int64_t>
-if host_system == 'linux' and host_machine.cpu_family() not in ['x86', 'x86_64']
-  libatomic_dep = cxx.find_library('atomic', required: false)
+if host_system == 'linux' and host_machine.cpu_family() in ['aarch64', 'arm']
+  libatomic_dep = cxx.find_library('atomic', required: get_option('cuda-nvmm'))
   if not libatomic_dep.found()
     subdir_done()
   endif
@@ -89,43 +89,52 @@ if host_system == 'windows'
     ])
   endif
 else
+  # We have NVMM with nvbufsurface.h on both Linux x86 and Jetson (aarch64)
   nvmm_opt = get_option('cuda-nvmm')
-  if not nvmm_opt.disabled()
+  fsmod = import('fs')
+  if nvmm_opt.allowed()
+    incdir_candidates = []
+
     nvmm_inc_opt = get_option('cuda-nvmm-include-path')
     if nvmm_inc_opt != ''
-      gstcuda_nvmm_inc = [include_directories(nvmm_inc_opt)]
+      incdir_candidates += [nvmm_inc_opt]
+    else
+      # try some other default locations
+      incdir_candidates = [
+        '/usr/src/jetson_multimedia_api/include',
+        '/opt/nvidia/deepstream/deepstream/sources/includes',
+      ]
     endif
 
-    if cc.has_header('nvbufsurface.h',
-                     include_directories: gstcuda_nvmm_inc,
-                     required: false)
-      have_nvbufsurface_h = true
-    # try some other default locations
-    elif cc.has_header('/usr/src/jetson_multimedia_api/include/nvbufsurface.h',
-	               required: false)
-      have_nvbufsurface_h = true
-      gstcuda_nvmm_inc = [include_directories('/usr/src/jetson_multimedia_api/include')]
-    elif cc.has_header('/opt/nvidia/deepstream/deepstream/sources/includes/nvbufsurface.h',
-                       required: false)
-      have_nvbufsurface_h = true
-      gstcuda_nvmm_inc = [include_directories('/opt/nvidia/deepstream/deepstream/sources/includes')]
-    endif
-    if nvmm_opt.enabled() and not have_nvbufsurface_h
+    foreach incdir: incdir_candidates
+      if fsmod.is_dir(incdir)
+        incdir = include_directories(incdir)
+        if cc.has_header('nvbufsurface.h',
+                         include_directories: incdir,
+                         required: false)
+          have_nvbufsurface_h = true
+          gstcuda_nvmm_inc = incdir
+          break
+        endif
+      endif
+    endforeach
+
+    if have_nvbufsurface_h
+      extra_args += ['-DHAVE_CUDA_NVMM']
+      # On Tegra, we also have libnvbufsurface.so, which is not present on x86
+      if host_machine.cpu_family() == 'aarch64'
+        # check if we have a tegra based system (jetson)
+        nvbuf_dep = cc.find_library('nvbufsurface', dirs: '/usr/lib/aarch64-linux-gnu/tegra/', required: nvmm_opt)
+        if nvbuf_dep.found()
+          extra_deps += [nvbuf_dep]
+          extra_args += ['-DHAVE_CUDA_NVMM_JETSON']
+        endif
+      endif
+    elif nvmm_opt.enabled()
       error('Could not find required header: "nvbufsurface.h"')
       subdir_done()
     endif
   endif
-
-  if have_nvbufsurface_h
-    extra_args += ['-DHAVE_CUDA_NVMM']
-
-    # check if we have a tegra based system (jetson)
-    nvbuf_dep = cc.find_library('nvbufsurface', dirs: '/usr/lib/aarch64-linux-gnu/tegra/', required: false)
-    if nvbuf_dep.found()
-      extra_deps += [nvbuf_dep]
-      extra_args += ['-DHAVE_CUDA_NVMM_JETSON']
-    endif
-  endif
 endif
 
 pkg_name = 'gstreamer-cuda-' + api_version