fix(linux): link matching bundled libva libraries (#5918)

AGENTS.md

@@ -10,7 +10,12 @@ the build directory.
 
 The project uses gtest as a test framework.
 
-Add or update tests for new or modified methods and code. Target 100% coverage on changed code.
+Add or update regression tests for new or modified source-code methods and behavior.
+Target 100% coverage on changed source code.
+
+The regression-test requirement does not apply to build-system files, such as CMake scripts and dependency configuration.
+Validate build-system changes with appropriate configuration, build, and lint checks.
+Do not add dedicated build-system regression-test projects or fixtures for these changes.
 
 ## Python tooling and formatting
 

cmake/FindLibva.cmake

@@ -10,30 +10,48 @@
 # find_path() and find_library() calls
 # cmake-format: on
 
-find_package(PkgConfig QUIET)
-if(PKG_CONFIG_FOUND)
-    pkg_check_modules(_LIBVA libva)
-    pkg_check_modules(_LIBVA_DRM libva-drm)
+if(EXISTS "${FFMPEG_PREPARED_BINARIES}/lib/libva.a")
+    # The display context ABI is private to libva. Keep its core, DRM backend,
+    # and headers from the same build as FFmpeg instead of mixing system libva.
+    set(LIBVA_INCLUDE_DIR "${FFMPEG_PREPARED_BINARIES}/include")
+    set(LIBVA_LIB "${FFMPEG_PREPARED_BINARIES}/lib/libva.a")
+    set(LIBVA_DRM_LIB "${FFMPEG_PREPARED_BINARIES}/lib/libva-drm.a")
+    foreach(required_file IN ITEMS
+            "${LIBVA_INCLUDE_DIR}/va/va.h"
+            "${LIBVA_INCLUDE_DIR}/va/va_drm.h"
+            "${LIBVA_DRM_LIB}")
+        if(NOT EXISTS "${required_file}")
+            message(FATAL_ERROR "The bundled libva package is incomplete: missing ${required_file}")
+        endif()
+    endforeach()
+    # libva-drm.pc does not declare the libdrm dependency of its static archive.
+    find_package(LIBDRM REQUIRED)
+else()
+    find_package(PkgConfig QUIET)
+    if(PKG_CONFIG_FOUND)
+        pkg_check_modules(_LIBVA libva)
+        pkg_check_modules(_LIBVA_DRM libva-drm)
+    endif()
+
+    find_path(
+            LIBVA_INCLUDE_DIR
+            NAMES va/va.h va/va_drm.h
+            HINTS ${_LIBVA_INCLUDE_DIRS}
+            PATHS /usr/include /usr/local/include /opt/local/include)
+
+    find_library(
+            LIBVA_LIB
+            NAMES ${_LIBVA_LIBRARIES} libva
+            HINTS ${_LIBVA_LIBRARY_DIRS}
+            PATHS /usr/lib /usr/local/lib /opt/local/lib)
+
+    find_library(
+            LIBVA_DRM_LIB
+            NAMES ${_LIBVA_DRM_LIBRARIES} libva-drm
+            HINTS ${_LIBVA_DRM_LIBRARY_DIRS}
+            PATHS /usr/lib /usr/local/lib /opt/local/lib)
 endif()
 
-find_path(
-        LIBVA_INCLUDE_DIR
-        NAMES va/va.h va/va_drm.h
-        HINTS ${_LIBVA_INCLUDE_DIRS}
-        PATHS /usr/include /usr/local/include /opt/local/include)
-
-find_library(
-        LIBVA_LIB
-        NAMES ${_LIBVA_LIBRARIES} libva
-        HINTS ${_LIBVA_LIBRARY_DIRS}
-        PATHS /usr/lib /usr/local/lib /opt/local/lib)
-
-find_library(
-        LIBVA_DRM_LIB
-        NAMES ${_LIBVA_DRM_LIBRARIES} libva-drm
-        HINTS ${_LIBVA_DRM_LIBRARY_DIRS}
-        PATHS /usr/lib /usr/local/lib /opt/local/lib)
-
 include(FindPackageHandleStandardArgs)
 find_package_handle_standard_args(Libva REQUIRED_VARS LIBVA_INCLUDE_DIR LIBVA_LIB LIBVA_DRM_LIB)
 mark_as_advanced(LIBVA_INCLUDE_DIR LIBVA_LIB LIBVA_DRM_LIB)
@@ -65,6 +83,13 @@ if(LIBVA_FOUND)
         endif()
 
         set_target_properties(Libva::drm PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "${LIBVA_INCLUDE_DIRS}")
+        if(EXISTS "${FFMPEG_PREPARED_BINARIES}/lib/libva.a")
+            set_target_properties(Libva::drm PROPERTIES
+                    INTERFACE_LINK_LIBRARIES "Libva::va;${LIBDRM_LIBRARIES}")
+        endif()
+    endif()
+    if(EXISTS "${FFMPEG_PREPARED_BINARIES}/lib/libva.a")
+        set(LIBVA_DRM_LIBRARIES Libva::drm)
     endif()
 
 endif()

cmake/dependencies/ffmpeg.cmake

@@ -176,6 +176,15 @@ else()
     list(APPEND FFMPEG_LIBRARIES ${FFMPEG_PLATFORM_LIBRARIES})
 endif()
 
+# Legacy library lists can also refer to libva backends by name. Resolve those
+# names to the matching archives whenever the FFmpeg package supplies libva.
+if(EXISTS "${FFMPEG_PREPARED_BINARIES}/lib/libva.a")
+    foreach(library IN ITEMS va va-drm va-x11)
+        list(TRANSFORM FFMPEG_LIBRARIES REPLACE
+                "^${library}$" "${FFMPEG_PREPARED_BINARIES}/lib/lib${library}.a")
+    endforeach()
+endif()
+
 # Shared packages supply the full static dependency list, including decoders.
 # Older packages retain the library list above.
 set(_sunshine_ffmpeg_pc "${FFMPEG_PREPARED_BINARIES}/lib/pkgconfig/libavcodec.pc")

docs/building.md

@@ -22,6 +22,10 @@ Sunshine's build and packaging automation uses packaged static Boost libraries o
 Ubuntu 26.04 or newer, macOS with Homebrew, Windows with MSYS2, and FreeBSD. Older supported distributions continue
 to use the CPM fallback because their repositories do not meet the minimum Boost version.
 
+When the prebuilt FFmpeg package supplies libva, Sunshine uses its bundled headers, core library, and DRM backend
+together. These components share a private display-context ABI and must come from the same libva build. The system
+still provides libdrm and the GPU's VA-API driver. FFmpeg packages without bundled libva use the system libva libraries.
+
 #### Prebuilt Web UI
 
 Sunshine releases publish the platform-independent Web UI as the `@lizardbyte/sunshine` package to npm and GitHub