wayland_vk: use FIFO if commit-timing and fifo protocols are available

A very long time annoyance with wayland was compositors indefinitely
blocking our vo thread if the surface gets occluded in some way. We've
worked around this by using mailbox and our own custom vsync function.
Thankfully it looks like people are finally solving this and with these
two protocols it should be possible to guarantee forward progress on
vulkan which means all the workarounds we do shouldn't be needed. So we
can just request fifo in this case as a default since all we want is
standard vsync blocking.

DOCS/man/options.rst

@@ -6014,7 +6014,10 @@ them.
 ``--wayland-disable-vsync=<yes|no>``
     Disable mpv's internal vsync for Wayland-based video output (default: no).
     This is mainly useful for benchmarking wayland VOs when combined with
-    ``video-sync=display-desync``, ``--audio=no``, and ``--untimed=yes``.
+    ``video-sync=display-desync``, ``--audio=no``, and ``--untimed=yes``. This
+    option has no affect if using ``--gpu-api=vulkan`` on a compositor that
+    supports the commit-timing and fifo protocols since mpv's internal vsync is
+    not used at all in that case.
 
 ``--wayland-edge-pixels-pointer=<value>``
     Defines the size of an edge border (default: 16) to initiate client side

video/out/meson.build

@@ -11,7 +11,8 @@ protocols = [[wl_protocol_dir, 'stable/presentation-time/presentation-time.xml']
 wl_protocols_source = []
 wl_protocols_headers = []
 
-foreach v: ['1.32']
+# TODO: bump this to 1.38 when it comes out
+foreach v: ['1.32', '1.37']
     features += {'wayland-protocols-' + v.replace('.', '-'):
         wayland['deps'][2].version().version_compare('>=' + v)}
 endforeach
@@ -21,6 +22,11 @@ if features['wayland-protocols-1-32']
                   [wl_protocol_dir, 'unstable/tablet/tablet-unstable-v2.xml']] # required by cursor-shape
 endif
 
+if features['wayland-protocols-1-37']
+    protocols += [[wl_protocol_dir, 'staging/commit-timing/commit-timing-v1.xml'],
+                  [wl_protocol_dir, 'staging/fifo/fifo-v1.xml']]
+endif
+
 foreach p: protocols
     xml = join_paths(p)
     wl_protocols_source += custom_target(xml.underscorify() + '_c',

video/out/vulkan/context_wayland.c

@@ -36,7 +36,7 @@ static void wayland_vk_swap_buffers(struct ra_ctx *ctx)
 {
     struct vo_wayland_state *wl = ctx->vo->wl;
 
-    if (!wl->opts->wl_disable_vsync)
+    if (!wl->has_commit_timing || !wl->has_fifo || !wl->opts->wl_disable_vsync)
         vo_wayland_wait_frame(wl);
 
     if (wl->use_present)
@@ -63,6 +63,7 @@ static bool wayland_vk_init(struct ra_ctx *ctx)
 {
     struct priv *p = ctx->priv = talloc_zero(ctx, struct priv);
     struct mpvk_ctx *vk = &p->vk;
+    struct vo_wayland_state *wl = ctx->vo->wl;
     int msgl = ctx->opts.probing ? MSGL_V : MSGL_ERR;
 
     if (!mpvk_init(vk, ctx, VK_KHR_WAYLAND_SURFACE_EXTENSION_NAME))
@@ -90,13 +91,14 @@ static bool wayland_vk_init(struct ra_ctx *ctx)
         goto error;
     }
 
-    /* Because in Wayland clients render whenever they receive a callback from
-     * the compositor, and the fact that the compositor usually stops sending
-     * callbacks once the surface is no longer visible, using FIFO here would
-     * mean the entire player would block on acquiring swapchain images. Hence,
-     * use MAILBOX to guarantee that there'll always be a swapchain image and
-     * the player won't block waiting on those */
-    if (!ra_vk_ctx_init(ctx, vk, params, VK_PRESENT_MODE_MAILBOX_KHR))
+    /* If the Wayland compositor does not support commit-timing and fifo
+     * protocols, the compositor will stop sending callbacks if the surface is
+     * no longer visible. That means using FIFO would block the entire vo thread
+     * which is just not good. Use MAILBOX for those compositors to avoid
+     * indefinite blocking. */
+    VkPresentModeKHR mode = wl->has_commit_timing && wl->has_fifo ? VK_PRESENT_MODE_FIFO_KHR :
+                                                                    VK_PRESENT_MODE_MAILBOX_KHR;
+    if (!ra_vk_ctx_init(ctx, vk, params, mode))
         goto error;
 
     ra_add_native_resource(ctx->ra, "wl", ctx->vo->wl->display);

video/out/wayland_common.c

@@ -56,6 +56,11 @@
 #include "cursor-shape-v1.h"
 #endif
 
+#if HAVE_WAYLAND_PROTOCOLS_1_37
+#include "commit-timing-v1.h"
+#include "fifo-v1.h"
+#endif
+
 #if WAYLAND_VERSION_MAJOR > 1 || WAYLAND_VERSION_MINOR >= 22
 #define HAVE_WAYLAND_1_22
 #endif
@@ -1568,6 +1573,11 @@ static void registry_handle_add(void *data, struct wl_registry *reg, uint32_t id
         wl->shm = wl_registry_bind(reg, id, &wl_shm_interface, ver);
     }
 
+    if (!strcmp(interface, wp_commit_timing_manager_v1_interface.name) && found++) {
+        ver = 1;
+        wl->has_commit_timing = true;
+    }
+
     if (!strcmp(interface, wp_content_type_manager_v1_interface.name) && found++) {
         ver = 1;
         wl->content_type_manager = wl_registry_bind(reg, id, &wp_content_type_manager_v1_interface, ver);
@@ -1578,6 +1588,11 @@ static void registry_handle_add(void *data, struct wl_registry *reg, uint32_t id
         wl->single_pixel_manager = wl_registry_bind(reg, id, &wp_single_pixel_buffer_manager_v1_interface, ver);
     }
 
+    if (!strcmp(interface, wp_fifo_manager_v1_interface.name) && found++) {
+        ver = 1;
+        wl->has_fifo = true;
+    }
+
     if (!strcmp(interface, wp_fractional_scale_manager_v1_interface.name) && found++) {
         ver = 1;
         wl->fractional_scale_manager = wl_registry_bind(reg, id, &wp_fractional_scale_manager_v1_interface, ver);

video/out/wayland_common.h

@@ -85,6 +85,9 @@ struct vo_wayland_state {
     int timeout_count;
     int wakeup_pipe[2];
 
+    /* commit-timing */
+    bool has_commit_timing;
+
     /* content-type */
     struct wp_content_type_manager_v1 *content_type_manager;
     struct wp_content_type_v1 *content_type;
@@ -94,6 +97,9 @@ struct vo_wayland_state {
     /* TODO: unvoid these if required wayland protocols is bumped to 1.32+ */
     void *cursor_shape_manager;
 
+    /* fifo */
+    bool has_fifo;
+
     /* fractional-scale */
     struct wp_fractional_scale_manager_v1 *fractional_scale_manager;
     struct wp_fractional_scale_v1 *fractional_scale;