va: allocator: Add hack for no fourcc when surface creation.

This patch adds general mechanism for handling specific hacks. In this
case for jpeg decoder in i965 driver, which cannot create surfaces
with fourcc specified.

From jpeg decoder to the allocator, which creates the surfaces,
there's a non-simple path: basedec pseudo-class adds a hacks guint32
which will be set by actual elements (vajpegdec, in this case) and
basedec will always set the hack to the allocator when the allocator
is instantiated.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1575>

subprojects/gst-plugins-bad/gst-libs/gst/va/gstva.h

@@ -32,6 +32,12 @@ typedef enum
   GST_VA_FEATURE_AUTO,
 } GstVaFeature;
 
+enum
+{
+  /* jpeg decoder in i965 driver cannot create surfaces with fourcc */
+  GST_VA_HACK_SURFACE_NO_FOURCC = 1 << 0,
+};
+
 #include <gst/va/va-prelude.h>
 #include <gst/va/va-enumtypes.h>
 #include <gst/va/gstvadisplay.h>

subprojects/gst-plugins-bad/gst-libs/gst/va/gstvaallocator.c

@@ -951,6 +951,8 @@ struct _GstVaAllocator
   GstVideoInfo info;
   guint usage_hint;
 
+  guint32 hacks;
+
   GstVaSurfaceCopy *copy;
 
   GstVaMemoryPool pool;
@@ -1556,7 +1558,8 @@ gst_va_allocator_try (GstAllocator * allocator)
     self->fourcc = 0;
     self->rt_format = gst_va_chroma_from_video_format (self->img_format);
   } else {
-    self->fourcc = gst_va_fourcc_from_video_format (self->surface_format);
+    if (G_LIKELY (!(self->hacks & GST_VA_HACK_SURFACE_NO_FOURCC)))
+      self->fourcc = gst_va_fourcc_from_video_format (self->surface_format);
     self->rt_format = gst_va_chroma_from_video_format (self->surface_format);
   }
 
@@ -1641,6 +1644,17 @@ gst_va_allocator_get_format (GstAllocator * allocator, GstVideoInfo * info,
   return TRUE;
 }
 
+void
+gst_va_allocator_set_hacks (GstAllocator * allocator, guint32 hacks)
+{
+  GstVaAllocator *self;
+
+  g_return_if_fail (GST_IS_VA_ALLOCATOR (allocator));
+  self = GST_VA_ALLOCATOR (allocator);
+
+  self->hacks = hacks;
+}
+
 /*============ Utilities =====================================================*/
 
 VASurfaceID

subprojects/gst-plugins-bad/gst-libs/gst/va/gstvaallocator.h

@@ -101,6 +101,9 @@ gboolean              gst_va_allocator_get_format         (GstAllocator * alloca
                                                            GstVideoInfo * info,
                                                            guint * usage_hint,
 							   GstVaFeature * use_derived);
+GST_VA_API
+void                  gst_va_allocator_set_hacks          (GstAllocator * allocator,
+                                                           guint32 hack);
 
 GST_VA_API
 VASurfaceID           gst_va_memory_get_surface           (GstMemory * mem);

subprojects/gst-plugins-bad/sys/va/gstvabasedec.c

@@ -228,6 +228,7 @@ _create_allocator (GstVaBaseDec * base, GstCaps * caps)
     GArray *surface_formats =
         gst_va_decoder_get_surface_formats (base->decoder);
     allocator = gst_va_allocator_new (base->display, surface_formats);
+    gst_va_allocator_set_hacks (allocator, base->hacks);
   }
 
   return allocator;

subprojects/gst-plugins-bad/sys/va/gstvabasedec.h

@@ -83,6 +83,8 @@ struct _GstVaBaseDec
   GstVideoConverter *convert;
 
   gboolean need_negotiation;
+
+  guint32 hacks;
 };
 
 struct _GstVaBaseDecClass