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screen-cast-stream-src: Support DMA buffer sharing

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Implement PipeWire's add_buffer and remove buffer, try and export
a DMA buffer first and, on failure, fallback to memfd.

When DMA buffers are successfully created and shared, blit the
framebuffer contents when drawing instead of downloading the pixels.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/1086
This commit is contained in:
Georges Basile Stavracas Neto 2019-12-09 10:07:29 -03:00
parent d366fb335d
commit 548073ec27
2 changed files with 164 additions and 27 deletions
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189
src/backends/meta-screen-cast-stream-src.c
View File

@ -25,6 +25,7 @@
#include "backends/meta-screen-cast-stream-src.h"
#include <errno.h>
#include <fcntl.h>
#include <pipewire/pipewire.h>
#include <spa/param/props.h>
#include <spa/param/format-utils.h>
@ -90,6 +91,8 @@ typedef struct _MetaScreenCastStreamSrcPrivate
uint64_t last_frame_timestamp_us;
GHashTable *dmabuf_handles;
int stream_width;
int stream_height;
} MetaScreenCastStreamSrcPrivate;
@ -139,6 +142,19 @@ meta_screen_cast_stream_src_record_frame (MetaScreenCastStreamSrc *src,
return klass->record_frame (src, data);
}
static gboolean
meta_screen_cast_stream_src_blit_to_framebuffer (MetaScreenCastStreamSrc *src,
CoglFramebuffer *framebuffer)
{
MetaScreenCastStreamSrcClass *klass =
META_SCREEN_CAST_STREAM_SRC_GET_CLASS (src);
if (klass->blit_to_framebuffer)
return klass->blit_to_framebuffer (src, framebuffer);
return FALSE;
}
static void
meta_screen_cast_stream_src_set_cursor_metadata (MetaScreenCastStreamSrc *src,
struct spa_meta_cursor *spa_meta_cursor)
@ -394,6 +410,33 @@ maybe_record_cursor (MetaScreenCastStreamSrc *src,
g_assert_not_reached ();
}
static gboolean
do_record_frame (MetaScreenCastStreamSrc *src,
struct spa_buffer *spa_buffer,
uint8_t *data)
{
MetaScreenCastStreamSrcPrivate *priv =
meta_screen_cast_stream_src_get_instance_private (src);
if (spa_buffer->datas[0].data ||
spa_buffer->datas[0].type == SPA_DATA_MemFd)
{
return meta_screen_cast_stream_src_record_frame (src, data);
}
else if (spa_buffer->datas[0].type == SPA_DATA_DmaBuf)
{
CoglDmaBufHandle *dmabuf_handle =
g_hash_table_lookup (priv->dmabuf_handles,
GINT_TO_POINTER (spa_buffer->datas[0].fd));
CoglFramebuffer *dmabuf_fbo =
cogl_dma_buf_handle_get_framebuffer (dmabuf_handle);
return meta_screen_cast_stream_src_blit_to_framebuffer (src, dmabuf_fbo);
}
return FALSE;
}
void
meta_screen_cast_stream_src_maybe_record_frame (MetaScreenCastStreamSrc *src)
{
@ -402,8 +445,7 @@ meta_screen_cast_stream_src_maybe_record_frame (MetaScreenCastStreamSrc *src)
MetaRectangle crop_rect;
struct pw_buffer *buffer;
struct spa_buffer *spa_buffer;
uint8_t *map = NULL;
uint8_t *data;
uint8_t *data = NULL;
uint64_t now_us;
now_us = g_get_monotonic_time ();
@ -424,32 +466,15 @@ meta_screen_cast_stream_src_maybe_record_frame (MetaScreenCastStreamSrc *src)
}
spa_buffer = buffer->buffer;
data = spa_buffer->datas[0].data;
if (spa_buffer->datas[0].data)
if (spa_buffer->datas[0].type != SPA_DATA_DmaBuf && !data)
{
data = spa_buffer->datas[0].data;
}
else if (spa_buffer->datas[0].type == SPA_DATA_MemFd)
{
map = mmap (NULL, spa_buffer->datas[0].maxsize + spa_buffer->datas[0].mapoffset,
PROT_READ | PROT_WRITE, MAP_SHARED,
spa_buffer->datas[0].fd, 0);
if (map == MAP_FAILED)
{
g_warning ("Failed to mmap pipewire stream buffer: %s",
strerror (errno));
return;
}
data = SPA_MEMBER (map, spa_buffer->datas[0].mapoffset, uint8_t);
}
else
{
g_warning ("Unhandled spa buffer type: %d", spa_buffer->datas[0].type);
g_critical ("Invalid buffer data");
return;
}
if (meta_screen_cast_stream_src_record_frame (src, data))
if (do_record_frame (src, spa_buffer, data))
{
struct spa_meta_region *spa_meta_video_crop;
@ -487,9 +512,6 @@ meta_screen_cast_stream_src_maybe_record_frame (MetaScreenCastStreamSrc *src)
priv->last_frame_timestamp_us = now_us;
if (map)
munmap (map, spa_buffer->datas[0].maxsize + spa_buffer->datas[0].mapoffset);
pw_stream_queue_buffer (priv->pipewire_stream, buffer);
}
@ -618,10 +640,116 @@ on_stream_param_changed (void *data,
pw_stream_update_params (priv->pipewire_stream, params, G_N_ELEMENTS (params));
}
static void
on_stream_add_buffer (void *data,
struct pw_buffer *buffer)
{
MetaScreenCastStreamSrc *src = data;
MetaScreenCastStreamSrcPrivate *priv =
meta_screen_cast_stream_src_get_instance_private (src);
CoglContext *context =
clutter_backend_get_cogl_context (clutter_get_default_backend ());
CoglRenderer *renderer = cogl_context_get_renderer (context);
g_autoptr (GError) error = NULL;
CoglDmaBufHandle *dmabuf_handle;
struct spa_buffer *spa_buffer = buffer->buffer;
struct spa_data *spa_data = spa_buffer->datas;
const int bpp = 4;
int stride;
stride = SPA_ROUND_UP_N (priv->video_format.size.width * bpp, 4);
spa_data[0].mapoffset = 0;
spa_data[0].maxsize = stride * priv->video_format.size.height;
dmabuf_handle = cogl_renderer_create_dma_buf (renderer,
priv->stream_width,
priv->stream_height,
&error);
if (error)
g_debug ("Error exporting DMA buffer handle: %s", error->message);
if (dmabuf_handle)
{
spa_data[0].type = SPA_DATA_DmaBuf;
spa_data[0].flags = SPA_DATA_FLAG_READWRITE;
spa_data[0].fd = cogl_dma_buf_handle_get_fd (dmabuf_handle);
spa_data[0].data = NULL;
g_hash_table_insert (priv->dmabuf_handles,
GINT_TO_POINTER (spa_data[0].fd),
dmabuf_handle);
}
else
{
unsigned int seals;
/* Fallback to a memfd buffer */
spa_data[0].type = SPA_DATA_MemFd;
spa_data[0].flags = SPA_DATA_FLAG_READWRITE;
spa_data[0].fd = memfd_create ("mutter-screen-cast-memfd",
MFD_CLOEXEC | MFD_ALLOW_SEALING);
if (spa_data[0].fd == -1)
{
g_critical ("Can't create memfd: %m");
return;
}
spa_data[0].mapoffset = 0;
spa_data[0].maxsize = stride * priv->video_format.size.height;
if (ftruncate (spa_data[0].fd, spa_data[0].maxsize) < 0)
{
g_critical ("Can't truncate to %d: %m", spa_data[0].maxsize);
return;
}
seals = F_SEAL_GROW | F_SEAL_SHRINK | F_SEAL_SEAL;
if (fcntl (spa_data[0].fd, F_ADD_SEALS, seals) == -1)
g_warning ("Failed to add seals: %m");
spa_data[0].data = mmap (NULL,
spa_data[0].maxsize,
PROT_READ | PROT_WRITE,
MAP_SHARED,
spa_data[0].fd,
spa_data[0].mapoffset);
if (spa_data[0].data == MAP_FAILED)
{
g_critical ("Failed to mmap memory: %m");
return;
}
}
}
static void
on_stream_remove_buffer (void *data,
struct pw_buffer *buffer)
{
MetaScreenCastStreamSrc *src = data;
MetaScreenCastStreamSrcPrivate *priv =
meta_screen_cast_stream_src_get_instance_private (src);
struct spa_buffer *spa_buffer = buffer->buffer;
struct spa_data *spa_data = spa_buffer->datas;
if (spa_data[0].type == SPA_DATA_DmaBuf)
{
if (!g_hash_table_remove (priv->dmabuf_handles, GINT_TO_POINTER (spa_data[0].fd)))
g_critical ("Failed to remove non-exported DMA buffer");
}
else if (spa_data[0].type == SPA_DATA_MemFd)
{
munmap (spa_data[0].data, spa_data[0].maxsize);
close (spa_data[0].fd);
}
}
static const struct pw_stream_events stream_events = {
PW_VERSION_STREAM_EVENTS,
.state_changed = on_stream_state_changed,
.param_changed = on_stream_param_changed,
.add_buffer = on_stream_add_buffer,
.remove_buffer = on_stream_remove_buffer,
};
static struct pw_stream *
@ -686,7 +814,7 @@ create_pipewire_stream (MetaScreenCastStreamSrc *src,
PW_DIRECTION_OUTPUT,
SPA_ID_INVALID,
(PW_STREAM_FLAG_DRIVER |
PW_STREAM_FLAG_MAP_BUFFERS),
PW_STREAM_FLAG_ALLOC_BUFFERS),
params, G_N_ELEMENTS (params));
if (result != 0)
{
@ -854,6 +982,7 @@ meta_screen_cast_stream_src_finalize (GObject *object)
if (meta_screen_cast_stream_src_is_enabled (src))
meta_screen_cast_stream_src_disable (src);
g_clear_pointer (&priv->dmabuf_handles, g_hash_table_destroy);
g_clear_pointer (&priv->pipewire_stream, pw_stream_destroy);
g_clear_pointer (&priv->pipewire_core, pw_core_disconnect);
g_clear_pointer (&priv->pipewire_context, pw_context_destroy);
@ -905,6 +1034,12 @@ meta_screen_cast_stream_src_get_property (GObject *object,
static void
meta_screen_cast_stream_src_init (MetaScreenCastStreamSrc *src)
{
MetaScreenCastStreamSrcPrivate *priv =
meta_screen_cast_stream_src_get_instance_private (src);
priv->dmabuf_handles =
g_hash_table_new_full (NULL, NULL, NULL,
(GDestroyNotify) cogl_dma_buf_handle_free);
}
static void

2
src/backends/meta-screen-cast-stream-src.h
View File

@ -55,6 +55,8 @@ struct _MetaScreenCastStreamSrcClass
void (* disable) (MetaScreenCastStreamSrc *src);
gboolean (* record_frame) (MetaScreenCastStreamSrc *src,
uint8_t *data);
gboolean (* blit_to_framebuffer) (MetaScreenCastStreamSrc *src,
CoglFramebuffer *framebuffer);
gboolean (* get_videocrop) (MetaScreenCastStreamSrc *src,
MetaRectangle *crop_rect);
void (* set_cursor_metadata) (MetaScreenCastStreamSrc *src,