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wayland/dma-buf: Prefer sync_file for dma-buf readiness source

Similarly to https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3389,
this avoids over-synchronization due to the client reading from the
buffer, e.g. if drawing a frame re-uses the previous frame contents.

v2:
* Rename owned_fd → owned_sync_fd (Sebastian Wick)
* Put curly braces around do/while loop

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3408>
This commit is contained in:
Michel Dänzer 2023-11-18 16:30:06 +01:00 committed by Marge Bot
parent 0e471bcea7
commit c47730894e

View file

@ -39,6 +39,8 @@
#include <drm_fourcc.h>
#include <glib/gstdio.h>
#include <linux/dma-buf.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
@ -838,10 +840,11 @@ typedef struct _MetaWaylandDmaBufSource
gpointer user_data;
gpointer fd_tags[META_WAYLAND_DMA_BUF_MAX_FDS];
int owned_sync_fd[META_WAYLAND_DMA_BUF_MAX_FDS];
} MetaWaylandDmaBufSource;
static gboolean
meta_wayland_dma_buf_fd_readable (int fd)
is_fd_readable (int fd)
{
GPollFD poll_fd;
@ -872,11 +875,16 @@ meta_wayland_dma_buf_source_dispatch (GSource *base,
for (i = 0; i < META_WAYLAND_DMA_BUF_MAX_FDS; i++)
{
gpointer fd_tag = source->fd_tags[i];
int fd;
if (!fd_tag)
continue;
if (!meta_wayland_dma_buf_fd_readable (dma_buf->fds[i]))
fd = source->owned_sync_fd[i];
if (fd < 0)
fd = dma_buf->fds[i];
if (!is_fd_readable (fd))
{
ready = FALSE;
continue;
@ -884,6 +892,7 @@ meta_wayland_dma_buf_source_dispatch (GSource *base,
g_source_remove_unix_fd (&source->base, fd_tag);
source->fd_tags[i] = NULL;
g_clear_fd (&source->owned_sync_fd[i], NULL);
}
if (!ready)
@ -910,6 +919,7 @@ meta_wayland_dma_buf_source_finalize (GSource *base)
{
g_source_remove_unix_fd (&source->base, fd_tag);
source->fd_tags[i] = NULL;
g_clear_fd (&source->owned_sync_fd[i], NULL);
}
}
@ -927,6 +937,7 @@ create_source (MetaWaylandBuffer *buffer,
gpointer user_data)
{
MetaWaylandDmaBufSource *source;
int i;
source =
(MetaWaylandDmaBufSource *) g_source_new (&meta_wayland_dma_buf_source_funcs,
@ -937,9 +948,30 @@ create_source (MetaWaylandBuffer *buffer,
source->dispatch = dispatch;
source->user_data = user_data;
for (i = 0; i < META_WAYLAND_DMA_BUF_MAX_FDS; i++)
source->owned_sync_fd[i] = -1;
return source;
}
static int
get_sync_file (int dma_buf_fd)
{
struct dma_buf_export_sync_file dbesf = { .flags = DMA_BUF_SYNC_READ };
int ret;
do
{
ret = ioctl (dma_buf_fd, DMA_BUF_IOCTL_EXPORT_SYNC_FILE, &dbesf);
}
while (ret == -1 && errno == EINTR);
if (ret == 0)
return dbesf.fd;
return -1;
}
/**
* meta_wayland_dma_buf_create_source:
* @buffer: A #MetaWaylandBuffer object
@ -973,12 +1005,16 @@ meta_wayland_dma_buf_create_source (MetaWaylandBuffer *buffer,
if (fd < 0)
break;
if (meta_wayland_dma_buf_fd_readable (fd))
if (is_fd_readable (fd))
continue;
if (!source)
source = create_source (buffer, dispatch, user_data);
source->owned_sync_fd[i] = get_sync_file (fd);
if (source->owned_sync_fd[i] >= 0)
fd = source->owned_sync_fd[i];
source->fd_tags[i] = g_source_add_unix_fd (&source->base, fd, G_IO_IN);
}