[PATCH v1 7/7] ui/spice: Create another texture with linear layout when gl=on is enabled

[Vivek Kasireddy <vivek.kasireddy@intel.com>]

Since most encoders (invoked by Spice) may not work with tiled memory
associated with a texture, we need to create another texture that has
linear memory layout and use that instead.

Note that, there does not seem to be a direct way to indicate to the
GL implementation that a texture's backing memory needs to be linear.
Instead, we have to do it in a roundabout way where we first need to
create a tiled texture and obtain a dmabuf fd associated with it via
EGL. Next, we have to create a memory object by importing the dmabuf
fd created earlier and finally create a linear texture by using the
memory object as the texture storage mechanism.

Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Frediano Ziglio <freddy77@gmail.com>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
---
 ui/spice-display.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/ui/spice-display.c b/ui/spice-display.c
index 08b4aec921..94cb378dbe 100644
--- a/ui/spice-display.c
+++ b/ui/spice-display.c
@@ -893,6 +893,7 @@ static void spice_gl_switch(DisplayChangeListener *dcl,
 {
     SimpleSpiceDisplay *ssd = container_of(dcl, SimpleSpiceDisplay, dcl);
     EGLint stride, fourcc;
+    GLuint texture = 0;
     int fd;
 
     if (ssd->ds) {
@@ -912,6 +913,38 @@ static void spice_gl_switch(DisplayChangeListener *dcl,
             return;
         }
 
+        if (remote_client && surface_format(ssd->ds) != PIXMAN_r5g6b5) {
+            /*
+             * We really want to ensure that the memory layout of the texture
+             * is linear; otherwise, the encoder's output may show corruption.
+             */
+            surface_gl_create_texture_from_fd(ssd->ds, fd, &texture);
+
+            /*
+             * A successful return after glImportMemoryFdEXT() means that
+             * the ownership of fd has been passed to GL. In other words,
+             * the fd we got above should not be used anymore.
+             */
+            if (texture > 0) {
+                fd = egl_get_fd_for_texture(texture,
+                                            &stride, &fourcc,
+                                            NULL);
+                if (fd < 0) {
+                    glDeleteTextures(1, &texture);
+                    fd = egl_get_fd_for_texture(ssd->ds->texture,
+                                                &stride, &fourcc,
+                                                NULL);
+                    if (fd < 0) {
+                        surface_gl_destroy_texture(ssd->gls, ssd->ds);
+                        return;
+                    }
+                } else {
+                    surface_gl_destroy_texture(ssd->gls, ssd->ds);
+                    ssd->ds->texture = texture;
+                }
+            }
+        }
+
         trace_qemu_spice_gl_surface(ssd->qxl.id,
                                     surface_width(ssd->ds),
                                     surface_height(ssd->ds),
-- 
2.39.2