qsvdec: Allow use of hw_device_ctx to make the internal session

(cherry picked from commit 8848ba0b)

libavcodec/qsvdec.c

@@ -42,7 +42,7 @@
 #include "qsvdec.h"
 
 static int qsv_init_session(AVCodecContext *avctx, QSVContext *q, mfxSession session,
-                            AVBufferRef *hw_frames_ref)
+                            AVBufferRef *hw_frames_ref, AVBufferRef *hw_device_ref)
 {
     int ret;
 
@@ -67,6 +67,18 @@ static int qsv_init_session(AVCodecContext *avctx, QSVContext *q, mfxSession ses
             return ret;
         }
 
+        q->session = q->internal_session;
+    } else if (hw_device_ref) {
+        if (q->internal_session) {
+            MFXClose(q->internal_session);
+            q->internal_session = NULL;
+        }
+
+        ret = ff_qsv_init_session_device(avctx, &q->internal_session,
+                                         hw_device_ref, q->load_plugins);
+        if (ret < 0)
+            return ret;
+
         q->session = q->internal_session;
     } else {
         if (!q->internal_session) {
@@ -133,7 +145,7 @@ static int qsv_decode_init(AVCodecContext *avctx, QSVContext *q)
         iopattern = MFX_IOPATTERN_OUT_SYSTEM_MEMORY;
     q->iopattern = iopattern;
 
-    ret = qsv_init_session(avctx, q, session, avctx->hw_frames_ctx);
+    ret = qsv_init_session(avctx, q, session, avctx->hw_frames_ctx, avctx->hw_device_ctx);
     if (ret < 0) {
         av_log(avctx, AV_LOG_ERROR, "Error initializing an MFX session\n");
         return ret;