From 1d3de2a1d70ee3738892b51672481a26ba44e83d Mon Sep 17 00:00:00 2001
From: pineappleEA <pineaea@gmail.com>
Date: Sat, 27 Nov 2021 01:35:58 +0100
Subject: [PATCH] early-access version 2244

---
 README.md                                     |  2 +-
 .../command_classes/codecs/codec.cpp          | 43 ++++++++++++++++++-
 2 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 110a8ae4d..d5fa567a6 100755
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 yuzu emulator early access
 =============
 
-This is the source code for early-access 2243.
+This is the source code for early-access 2244.
 
 ## Legal Notice
 
diff --git a/src/video_core/command_classes/codecs/codec.cpp b/src/video_core/command_classes/codecs/codec.cpp
index 916277811..02d309170 100755
--- a/src/video_core/command_classes/codecs/codec.cpp
+++ b/src/video_core/command_classes/codecs/codec.cpp
@@ -2,6 +2,8 @@
 // Licensed under GPLv2 or any later version
 // Refer to the license.txt file included.
 
+#include <algorithm>
+#include <cstdio>
 #include <fstream>
 #include <vector>
 #include "common/assert.h"
@@ -59,6 +61,34 @@ Codec::~Codec() {
     av_buffer_unref(&av_gpu_decoder);
 }
 
+#ifdef LIBVA_FOUND
+// List all the currently loaded Linux modules
+static std::vector<std::string> ListLinuxKernelModules() {
+    using FILEPtr = std::unique_ptr<FILE, decltype(&std::fclose)>;
+    auto module_listing = FILEPtr{fopen("/proc/modules", "rt"), std::fclose};
+    std::vector<std::string> modules{};
+    if (!module_listing) {
+        LOG_WARNING(Service_NVDRV, "Could not open /proc/modules to collect available modules");
+        return modules;
+    }
+    char* buffer = nullptr;
+    size_t buf_len = 0;
+    while (getline(&buffer, &buf_len, module_listing.get()) != -1) {
+        // format for the module listing file (sysfs)
+        // <name> <module_size> <depended_by_count> <depended_by_names> <status> <load_address>
+        auto line = std::string(buffer);
+        // we are only interested in module names
+        auto name_pos = line.find_first_of(" ");
+        if (name_pos == std::string::npos) {
+            continue;
+        }
+        modules.push_back(line.erase(name_pos));
+    }
+    free(buffer);
+    return modules;
+}
+#endif
+
 bool Codec::CreateGpuAvDevice() {
 #if defined(LIBVA_FOUND)
     static constexpr std::array<const char*, 3> VAAPI_DRIVERS = {
@@ -67,8 +97,16 @@ bool Codec::CreateGpuAvDevice() {
         "amdgpu",
     };
     AVDictionary* hwdevice_options = nullptr;
+    const auto loaded_modules = ListLinuxKernelModules();
     av_dict_set(&hwdevice_options, "connection_type", "drm", 0);
     for (const auto& driver : VAAPI_DRIVERS) {
+        // first check if the target driver is loaded in the kernel
+        bool found = std::any_of(loaded_modules.begin(), loaded_modules.end(),
+                                 [&driver](const auto& module) { return module == driver; });
+        if (!found) {
+            LOG_DEBUG(Service_NVDRV, "Kernel driver {} is not loaded, trying the next one", driver);
+            continue;
+        }
         av_dict_set(&hwdevice_options, "kernel_driver", driver, 0);
         const int hwdevice_error = av_hwdevice_ctx_create(&av_gpu_decoder, AV_HWDEVICE_TYPE_VAAPI,
                                                           nullptr, hwdevice_options, 0);
@@ -85,11 +123,12 @@ bool Codec::CreateGpuAvDevice() {
 #endif
     static constexpr auto HW_CONFIG_METHOD = AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX;
     static constexpr std::array GPU_DECODER_TYPES{
+#ifdef linux
+        AV_HWDEVICE_TYPE_VDPAU,
+#endif
         AV_HWDEVICE_TYPE_CUDA,
 #ifdef _WIN32
         AV_HWDEVICE_TYPE_D3D11VA,
-#else
-        AV_HWDEVICE_TYPE_VDPAU,
 #endif
     };
     for (const auto& type : GPU_DECODER_TYPES) {