dcc: Create a stream associated with gl_draw for non-gl clients (v4)

For non-gl/remote clients, if there is no stream associated with
the DisplayChannel, then we create a new stream. Otherwise, we
just update the current stream's timestamp.

v2: (suggestions and fixups from Frediano)
- Moved the gl_draw_stream object from DCC to DC
- Moved the stream initialization code from display_channel_create_stream()
  into a separate function that is reused when creating gl_draw_stream

v3:
- Create a new primary surface whenever a new stream gets created

v4:
- Use nullptr instead of NULL and true instead of TRUE (Frediano)
- Create the stream as part of gl scanout instead of gl draw operation
  so that if would be easily possible to obtain key params such as
  stride, flags, etc
- Store key params such as fd, flags, stride, etc in the stream so that
  we do not have to look at scanout again

Cc: Frediano Ziglio <freddy77@gmail.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: Dongwon Kim <dongwon.kim@intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>

server/dcc.cpp

@@ -495,17 +495,23 @@ RedSurfaceDestroyItem::RedSurfaceDestroyItem(uint32_t surface_id)
 RedPipeItemPtr dcc_gl_scanout_item_new(RedChannelClient *rcc, void *data, int num)
 {
     auto dcc = static_cast<DisplayChannelClient *>(rcc);
+    auto scanout = static_cast<SpiceMsgDisplayGlScanoutUnix *>(data);
 
     if (dcc->is_gl_client()) {
         return red::make_shared<RedGlScanoutUnixItem>();
     } else if (rcc->test_remote_cap(SPICE_DISPLAY_CAP_MULTI_CODEC)) {
-        return RedPipeItemPtr();
+        if (!display_channel_create_gl_draw_stream(dcc, scanout)) {
+            red_channel_warning(rcc->get_channel(),
+                                "Cannot create GL stream");
+            rcc->disconnect();
+        }
     } else {
         red_channel_warning(rcc->get_channel(),
                             "Client does not support GL scanout or multiple codecs");
         rcc->disconnect();
-        return RedPipeItemPtr();
     }
+
+    return RedPipeItemPtr();
 }
 
 XXX_CAST(RedChannelClient, DisplayChannelClient, DISPLAY_CHANNEL_CLIENT);
@@ -523,6 +529,15 @@ RedPipeItemPtr dcc_gl_draw_item_new(RedChannelClient *rcc, void *data, int num)
         return RedPipeItemPtr();
     }
 
+    if (!dcc->is_gl_client()) {
+        if (!display_channel_update_gl_draw_stream(dcc, draw)) {
+            red_channel_warning(rcc->get_channel(),
+                                "Cannot update GL stream");
+            rcc->disconnect();
+            return RedPipeItemPtr();
+        }
+    }
+
     dcc->priv->gl_draw_ongoing = TRUE;
     auto item = red::make_shared<RedGlDrawItem>();
     item->draw = *draw;

server/display-channel-private.h

@@ -110,6 +110,7 @@ struct DisplayChannelPrivate
     uint32_t stream_count;
     std::array<VideoStream, NUM_STREAMS> streams_buf;
     VideoStream *free_streams;
+    VideoStream *gl_draw_stream;
     Ring streams;
     std::array<ItemTrace, NUM_TRACE_ITEMS> items_trace;
     uint32_t next_item_trace;

server/display-channel.cpp

@@ -2172,6 +2172,7 @@ display_channel_new(RedsState *reds, QXLInstance *qxl,
                                          video_codecs, n_surfaces);
     if (display) {
         display_channel_set_stream_video(display.get(), stream_video);
+        display->priv->gl_draw_stream = nullptr;
     }
     return display;
 }

server/video-stream.cpp

@@ -20,6 +20,7 @@
 #include "display-channel-private.h"
 #include "main-channel-client.h"
 #include "red-client.h"
+#include "red-qxl.h"
 
 #define FPS_TEST_INTERVAL 1
 #define FOREACH_STREAMS(display, item)                  \
@@ -366,7 +367,55 @@ static VideoStream *display_channel_stream_try_new(DisplayChannel *display)
     return stream;
 }
 
-static void display_channel_create_stream(DisplayChannel *display, Drawable *drawable)
+static void display_channel_init_stream(DisplayChannel *display,
+                                        VideoStream *stream,
+                                        Drawable *drawable,
+                                        SpiceRect* src_rect)
+{
+    SpiceBitmap *bitmap;
+    uint64_t duration;
+
+    ring_add(&display->priv->streams, &stream->link);
+    stream->last_time = spice_get_monotonic_time_ns();
+    stream->width = src_rect->right - src_rect->left;
+    stream->height = src_rect->bottom - src_rect->top;
+    stream->dest_area = *src_rect;
+    stream->refs = 1;
+    stream->input_fps = MAX_FPS * 2;
+    stream->num_input_frames = 0;
+    stream->input_fps_start_time = stream->last_time;
+    display->priv->streams_size_total += stream->width * stream->height;
+    display->priv->stream_count++;
+
+    stream->current = drawable;
+    if (drawable) {
+        drawable->stream = stream;
+        stream->last_time = drawable->creation_time;
+        stream->dest_area = drawable->red_drawable->bbox;
+        bitmap = &drawable->red_drawable->u.copy.src_bitmap->u.bitmap;
+        stream->top_down = !!(bitmap->flags & SPICE_BITMAP_FLAGS_TOP_DOWN);
+
+        /* Provide an fps estimate the video encoder can use when initializing
+         * based on the frames that lead to the creation of the stream. Round
+         * to the nearest integer, for instance 24 for 23.976.
+         */
+        duration = drawable->creation_time - drawable->first_frame_time;
+        if (duration > NSEC_PER_SEC * drawable->frames_count / MAX_FPS) {
+            stream->input_fps = (NSEC_PER_SEC * drawable->frames_count + duration / 2) / duration;
+        } else {
+            stream->input_fps = MAX_FPS;
+        }
+    }
+
+    spice_debug("stream %d %dx%d (%d, %d) (%d, %d) %u fps",
+                display_channel_get_video_stream_id(display, stream), stream->width,
+                stream->height, stream->dest_area.left, stream->dest_area.top,
+                stream->dest_area.right, stream->dest_area.bottom,
+                stream->input_fps);
+}
+
+static void display_channel_create_stream(DisplayChannel *display,
+                                          Drawable *drawable)
 {
     DisplayChannelClient *dcc;
     VideoStream *stream;
@@ -381,38 +430,91 @@ static void display_channel_create_stream(DisplayChannel *display, Drawable *dra
     spice_assert(drawable->red_drawable->type == QXL_DRAW_COPY);
     src_rect = &drawable->red_drawable->u.copy.src_area;
 
-    ring_add(&display->priv->streams, &stream->link);
-    stream->current = drawable;
-    stream->last_time = drawable->creation_time;
-    stream->width = src_rect->right - src_rect->left;
-    stream->height = src_rect->bottom - src_rect->top;
-    stream->dest_area = drawable->red_drawable->bbox;
-    stream->refs = 1;
-    SpiceBitmap *bitmap = &drawable->red_drawable->u.copy.src_bitmap->u.bitmap;
-    stream->top_down = !!(bitmap->flags & SPICE_BITMAP_FLAGS_TOP_DOWN);
-    drawable->stream = stream;
-    /* Provide an fps estimate the video encoder can use when initializing
-     * based on the frames that lead to the creation of the stream. Round to
-     * the nearest integer, for instance 24 for 23.976.
-     */
-    uint64_t duration = drawable->creation_time - drawable->first_frame_time;
-    if (duration > NSEC_PER_SEC * drawable->frames_count / MAX_FPS) {
-        stream->input_fps = (NSEC_PER_SEC * drawable->frames_count + duration / 2) / duration;
-    } else {
-        stream->input_fps = MAX_FPS;
-    }
-    stream->num_input_frames = 0;
-    stream->input_fps_start_time = drawable->creation_time;
-    display->priv->streams_size_total += stream->width * stream->height;
-    display->priv->stream_count++;
+    display_channel_init_stream(display, stream, drawable, src_rect);
     FOREACH_DCC(display, dcc) {
         dcc_create_stream(dcc, stream);
     }
-    spice_debug("stream %d %dx%d (%d, %d) (%d, %d) %u fps",
-                display_channel_get_video_stream_id(display, stream), stream->width,
-                stream->height, stream->dest_area.left, stream->dest_area.top,
-                stream->dest_area.right, stream->dest_area.bottom,
-                stream->input_fps);
+}
+
+bool display_channel_create_gl_draw_stream(DisplayChannelClient *dcc,
+                                           SpiceMsgDisplayGlScanoutUnix *scanout)
+{
+    DisplayChannel *display = DCC_TO_DC(dcc);
+    QXLInstance* qxl = display->priv->qxl;
+    VideoStream *stream;
+
+    if (!scanout) {
+        scanout = red_qxl_get_gl_scanout(qxl);
+        /* If the scanout is NULL, it could mean the scanout is explicitly
+         * (or temporarily) disabled, which is not an error condition.
+         */
+        if (!scanout) {
+            return true;
+        }
+    }
+
+    SpiceRect dest_area = {
+        .left = 0,
+        .top = 0,
+        .right = scanout->width,
+        .bottom = scanout->height
+    };
+
+    if (display->priv->surfaces[0]) {
+        display_channel_surface_id_unref(display, 0);
+    }
+    display_channel_create_surface(display, 0, scanout->width,
+                                   scanout->height, scanout->stride,
+                                   SPICE_SURFACE_FMT_32_xRGB,
+                                   nullptr, true, true);
+
+    display_channel_set_monitors_config_to_primary(display);
+    display_channel_push_monitors_config(display);
+    display->pipes_add_empty_msg(SPICE_MSG_DISPLAY_MARK);
+    display->push();
+
+    if (!(stream = display_channel_stream_try_new(display))) {
+        red_qxl_put_gl_scanout(qxl, scanout);
+        return false;
+    }
+
+    stream->top_down = (scanout->flags & SPICE_GL_SCANOUT_FLAGS_Y0TOP) ? 0 : 1;
+    stream->stride = scanout->stride;
+    stream->drm_dma_buf_fd = scanout->drm_dma_buf_fd;
+    display->priv->gl_draw_stream = stream;
+    display_channel_init_stream(display, stream, nullptr, &dest_area);
+    dcc_create_stream(dcc, stream);
+
+    red_qxl_put_gl_scanout(qxl, scanout);
+    return true;
+}
+
+bool display_channel_update_gl_draw_stream(DisplayChannelClient *dcc,
+                                           const SpiceMsgDisplayGlDraw *draw)
+{
+    DisplayChannel *display = DCC_TO_DC(dcc);
+    VideoStream *stream = display->priv->gl_draw_stream;
+    SpiceRect dest_area = {
+        .left = draw->x,
+        .top = draw->y,
+        .right = draw->w,
+        .bottom = draw->h
+    };
+
+    if (stream) {
+        stream->width = draw->w;
+        stream->height = draw->h;
+        stream->dest_area = dest_area;
+        stream->last_time = spice_get_monotonic_time_ns();
+        return true;
+    }
+
+    /* Ideally, the stream should be created as part of gl scanout operation
+     * but when there are no clients connected, a stream won't be created.
+     * However, when clients start connecting, a gl draw will happen first
+     * which is why we need to create a stream below.
+     */
+    return display_channel_create_gl_draw_stream(dcc, nullptr);
 }
 
 // returns whether a stream was created

server/video-stream.h

@@ -113,6 +113,8 @@ struct VideoStream {
     red_time_t last_time;
     int width;
     int height;
+    int stride;
+    int drm_dma_buf_fd;
     SpiceRect dest_area;
     int top_down;
     VideoStream *next;
@@ -124,6 +126,10 @@ struct VideoStream {
 };
 
 void display_channel_init_video_streams(DisplayChannel *display);
+bool display_channel_create_gl_draw_stream(DisplayChannelClient *dcc,
+                                           SpiceMsgDisplayGlScanoutUnix *scanout);
+bool display_channel_update_gl_draw_stream(DisplayChannelClient *dcc,
+                                           const SpiceMsgDisplayGlDraw *draw);
 void video_stream_stop(DisplayChannel *display, VideoStream *stream);
 void video_stream_trace_update(DisplayChannel *display, Drawable *drawable);
 void video_stream_maintenance(DisplayChannel *display, Drawable *candidate,