There is a race condition where g_drm_device_type can be left set to
DRM_DEVICE_RENDERNODES when it shouldn't.
If thread 1 comes in and falls into the last else statement setting up both
RENDERNODES and LEGACY types. And begins to process the first type (RENDERNODES),
it sets g_drm_device_type = RENDERNODES.
Now when thread 2 comes in and sees g_drm_device_type is RENDERNODES, it queues
up that type to be tried but then encounters the lock and has to wait until the
first thread finishes. Once the lock is acquired it will then proceed to ONLY try
RENDERNODES and fail it. But it doesn't try LEGACY. And from then on, all future
attempts will only try RENDERNODES.
So to avoid this situation I have simply moved the acquisition of the lock higher
up in the attached patch.
https://bugzilla.gnome.org/show_bug.cgi?id=747914
Add a new generic helper function gst_vaapi_window_new() to create
a window without having the caller to check for the display type
himself. i.e. internally, there is now a GstVaapiDisplayClass hook
to create windows, and the actual backend implementation fills it in.
Add new generic helper functions gst_vaapi_texture_new_wrapped()
This is a simplification in view to supporting EGL.
Make gst_vaapi_display_get_display_type() return the actual VA display
type. Conversely, add a gst_vaapi_display_get_class_type() function to
return the type of the GstVaapiDisplay instance. The former is used to
identify the display server onto which the application is running, and
the latter to identify the original object class.
Add support for DRM Render-Nodes. This is a new feature that appeared
in kernel 3.12 for experimentation purposes, but was later declared
stable enough in kernel 3.15 for getting enabled by default.
This allows headless usages without authentication at all, i.e. usages
through plain ssh connections is possible.
Make sure to initialize one GstVaapiDisplay at a time, even in threaded
environments. This makes sure the display cache is also consistent
during the whole display creation process. In the former implementation,
there were risks that display cache got updated in another thread.
Make it possible to add extra an extra filter to most of display cache
lookup functions so that the GstVaapiDisplay instance can really match
a compatible and existing display by type, instead of relying on extra
string tags (e.g. "X11:" prefix, etc.).
Drop obsolete GST_VAAPI_IS_xxx() helper macros since we are no longer
deriving from GObject and so those were only checking for whether the
argument was NULL or not. This is now irrelevant, and even confusing
to some extent, because we no longer have type checking.
Note: this incurs more type checking (review) but the libgstvaapi is
rather small, so this is manageable.
