va: allocator: Use always lseek to get dmabuf size.

Gallium drivers historically have reported strange dmabuf sizes, from always
zero to the whole frame (multiple fds). The simplest solution is to use lseek
SEEK_END to get the prime descriptor size.

Also the allocator raises a warning if both values differ in order to report
it to driver.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/2574>

diff --git a/subprojects/gst-plugins-bad/gst-libs/gst/va/gstvaallocator.c b/subprojects/gst-plugins-bad/gst-libs/gst/va/gstvaallocator.c
index e541426..fb26ef7 100644 (file)
--- a/subprojects/gst-plugins-bad/gst-libs/gst/va/gstvaallocator.c
+++ b/subprojects/gst-plugins-bad/gst-libs/gst/va/gstvaallocator.c
@@ -594,11 +594,18 @@ gst_va_dmabuf_allocator_setup_buffer_full (GstAllocator * allocator,
 
   for (i = 0; i < desc.num_objects; i++) {
     gint fd = desc.objects[i].fd;
-    gsize size = desc.objects[i].size > 0 ?
-        desc.objects[i].size : _get_fd_size (fd);
+    /* don't rely on prime descriptor reported size since gallium drivers report
+     * different values */
+    gsize size = _get_fd_size (fd);
     GstMemory *mem = gst_dmabuf_allocator_alloc (allocator, fd, size);
     guint64 *drm_mod = g_new (guint64, 1);
 
+    if (size != desc.objects[i].size) {
+      GST_WARNING_OBJECT (self, "driver bug: fd size (%" G_GSIZE_FORMAT
+          ") differs from object descriptor size (%" G_GUINT32_FORMAT ")",
+          size, desc.objects[i].size);
+    }
+
     object_offset[i] = gst_buffer_get_size (buffer);
     gst_buffer_append_memory (buffer, mem);
     buf->mems[i] = mem;