mpv/video/out/vulkan/context_wayland.c

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/*
* This file is part of mpv.
*
* mpv is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* mpv is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include "video/out/gpu/context.h"
#include "video/out/present_sync.h"
#include "video/out/wayland_common.h"
#include "common.h"
#include "context.h"
#include "utils.h"
struct priv {
struct mpvk_ctx vk;
};
static bool wayland_vk_check_visible(struct ra_ctx *ctx)
wayland: only render if we have frame callback Back in the olden days, mpv's wayland backend was driven by the frame callback. This had several issues and was removed in favor of the current approach which allowed some advanced features (like display-resample and presentation time) to actually work properly. However as a consequence, it meant that mpv always rendered, even if the surface was hidden. Wayland people consider this "wasteful" (and well they aren't wrong). This commit aims to avoid wasteful rendering by doing some additional checks in the swapchain. There's three main parts to this. 1. Wayland EGL now uses an external swapchain (like the drm context). Before we start a new frame, we check to see if we are waiting on a callback from the compositor. If there is no wait, then go ahead and proceed to render the frame, swap buffers, and then initiate vo_wayland_wait_frame to poll (with a timeout) for the next potential callback. If we are still waiting on callback from the compositor when starting a new frame, then we simple skip rendering it entirely until the surface comes back into view. 2. Wayland on vulkan has essentially the same approach although the details are a little different. The ra_vk_ctx does not have support for an external swapchain and although such a mechanism could theoretically be added, it doesn't make much sense with libplacebo. Instead, start_frame was added as a param and used to check for callback. 3. For wlshm, it's simply a matter of adding frame callback to it, leveraging vo_wayland_wait_frame, and using the frame callback value to whether or not to draw the image.
2020-09-18 17:29:53 +00:00
{
return vo_wayland_check_visible(ctx->vo);
wayland: only render if we have frame callback Back in the olden days, mpv's wayland backend was driven by the frame callback. This had several issues and was removed in favor of the current approach which allowed some advanced features (like display-resample and presentation time) to actually work properly. However as a consequence, it meant that mpv always rendered, even if the surface was hidden. Wayland people consider this "wasteful" (and well they aren't wrong). This commit aims to avoid wasteful rendering by doing some additional checks in the swapchain. There's three main parts to this. 1. Wayland EGL now uses an external swapchain (like the drm context). Before we start a new frame, we check to see if we are waiting on a callback from the compositor. If there is no wait, then go ahead and proceed to render the frame, swap buffers, and then initiate vo_wayland_wait_frame to poll (with a timeout) for the next potential callback. If we are still waiting on callback from the compositor when starting a new frame, then we simple skip rendering it entirely until the surface comes back into view. 2. Wayland on vulkan has essentially the same approach although the details are a little different. The ra_vk_ctx does not have support for an external swapchain and although such a mechanism could theoretically be added, it doesn't make much sense with libplacebo. Instead, start_frame was added as a param and used to check for callback. 3. For wlshm, it's simply a matter of adding frame callback to it, leveraging vo_wayland_wait_frame, and using the frame callback value to whether or not to draw the image.
2020-09-18 17:29:53 +00:00
}
wayland: refactor presentation time The motivation for this change was a segfault caused by e107342 which has complicated reasons for occuring (i.e. I'm not 100% sure but I think it is a really weird race). The major part of this commit is moving the initialization of presentation listener to the frame_callback function. Calling it in swap_buffers worked fine but in practice it meant a lot of meaningless function calls if a window was hidden (the presentation would just be immediately discarded). By calling it in frame_callback, we ensure the listener is only created when it is possible to receive a presentation event. Of course calling the presentation listener in feedback_presented or feedback_discarded was considered, but ultimately these events are too slow. Receiving the ust/msc/sbc triplet here and then passing it to mpv results in higher vsync judder since there is (likely) not enough time before the next pageflip. By design, the frame callback is meant to give us as much time as possible before the next repaint so calling it here is probably optimal. Additionally, we can make better use of the feedback_discarded event. The wp_presentation_feedback should not be destroyed here. It will be taken care of either when we get feedback again or when the player quits. Instead what we can do is set a bool that tells wayland_sync_swap to update itself based on mp_time delta. In practice, the result is not any different than before, but it should be more understandable what is going on now. Of course, the segfault mentioned at the beginning is fixed with this as well.
2020-08-15 21:07:53 +00:00
static void wayland_vk_swap_buffers(struct ra_ctx *ctx)
{
struct vo_wayland_state *wl = ctx->vo->wl;
wayland: shuffle around the render loop again Take two. f4e89dd went wrong by moving vo_wayland_wait_frame before start_frame was called. Whether or not this matters depends on the compositor, but some weird things can happen. Basically, it's a scheduling issue. vo_wayland_wait_frame queues all events and sends them to the server to process (with no blocking if presentation time is available). If mpv changes state while rendering (and this function is called before every frame is drawn), then that event also gets dispatched and sent to the compositor. This, in some cases, can cause some funny behavior because the next frame gets attached to the surface while the old buffer is getting released. It's safer to call this function after the swap already happens and well before mpv calls its next draw. There's no weird scheduling of events, and the compositor log is more normal. The second part of this is to fix some stuttering issues. This is mostly just conjecture, but probably what was happening was this thing called "composition". The easiest way to see this is to play a video on the default audio sync mode (probably easiest to see on a typical 23.976 video). Have that in a window and float it over firefox (floating windows are bloat on a tiling wm anyway). Then in firefox, do some short bursts of smooth scrolling (likely uses egl). Some stutter in video rendering could be observed, particularly in panning shots. Compositors are supposed to prevent tearing so what likely was happening was that the compositor was simply holding the buffer a wee bit longer to make sure it happened in sync with the smooth scrolling. Because the mpv code waits precisely on presentation time, the loop would timeout on occasion instead of receiving the frame callback. This would then lead to a skipped frame when rendering and thus causing stuttering. The fix is simple: just only count consecutive timeouts as not receiving frame callback. If a compositor holds the mpv buffer slightly longer to avoid tearing, then we will definitely receive frame callback on the next round of the render loop. This logic also appears to be sound for plasma (funfact: Plasma always returns frame callback even when the window is hidden. Not sure what's up with that, but luckily it doesn't matter to us.), so get rid of the goofy 1/vblank_time thing and just keep it a simple > 1 check.
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if (!wl->opts->disable_vsync)
vo_wayland_wait_frame(wl);
if (wl->use_present)
present_sync_swap(wl->present);
}
static void wayland_vk_get_vsync(struct ra_ctx *ctx, struct vo_vsync_info *info)
{
struct vo_wayland_state *wl = ctx->vo->wl;
if (wl->use_present)
present_sync_get_info(wl->present, info);
wayland: use callback flag + poll for buffer swap The old way of using wayland in mpv relied on an external renderloop for semi-accurate timings. This had multiple issues though. Display sync would break whenever the window was hidden (since the frame callback stopped being executed) which was really annoying. Also the entire external renderloop logic was kind of fragile and didn't play well with mpv's internal structure (i.e. using presentation time in that old paradigm breaks stats.lua). Basically the problem is that swap buffers blocks on wayland which is crap whenever you hide the mpv window since it looks up the entire player. So you have to make swap buffers not block, but this has a different problem. Timings will be terrible if you use the unblocked swap buffers call. Based on some discussion in #wayland, the trick here is relatively simple and works well enough for our purposes. Instead we basically build a way to block with a timeout in the wayland buffer swap functions. A bool is set in the frame callback function that indicates whether or not mpv is waiting for a frame to be displayed. In the actual buffer swap function, we enter into a while loop waiting for this flag to be set. At the same time, the wl_display is polled to block the thread and wakeup if it receives any events from the compositor. This loop only breaks if enough time has passed or if the frame callback bool is received. In the near future, it is better to set whether or not frame a frame has been displayed in the presentation feedback. However as a first pass, doing it in the frame callback is more than good enough. The "downside" is that we render frames that aren't actually shown on screen when the player is hidden (it seems like wayland people don't like that). But who cares. Accurate timings are way more important. It's probably not too hard to add that behavior back in the player though.
2019-10-07 20:58:36 +00:00
}
static void wayland_vk_uninit(struct ra_ctx *ctx)
{
struct priv *p = ctx->priv;
ra_vk_ctx_uninit(ctx);
mpvk_uninit(&p->vk);
vo_wayland_uninit(ctx->vo);
}
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;
int msgl = ctx->opts.probing ? MSGL_V : MSGL_ERR;
if (!mpvk_init(vk, ctx, VK_KHR_WAYLAND_SURFACE_EXTENSION_NAME))
goto error;
if (!vo_wayland_init(ctx->vo))
goto error;
VkWaylandSurfaceCreateInfoKHR wlinfo = {
.sType = VK_STRUCTURE_TYPE_WAYLAND_SURFACE_CREATE_INFO_KHR,
.display = ctx->vo->wl->display,
.surface = ctx->vo->wl->surface,
};
wayland: use callback flag + poll for buffer swap The old way of using wayland in mpv relied on an external renderloop for semi-accurate timings. This had multiple issues though. Display sync would break whenever the window was hidden (since the frame callback stopped being executed) which was really annoying. Also the entire external renderloop logic was kind of fragile and didn't play well with mpv's internal structure (i.e. using presentation time in that old paradigm breaks stats.lua). Basically the problem is that swap buffers blocks on wayland which is crap whenever you hide the mpv window since it looks up the entire player. So you have to make swap buffers not block, but this has a different problem. Timings will be terrible if you use the unblocked swap buffers call. Based on some discussion in #wayland, the trick here is relatively simple and works well enough for our purposes. Instead we basically build a way to block with a timeout in the wayland buffer swap functions. A bool is set in the frame callback function that indicates whether or not mpv is waiting for a frame to be displayed. In the actual buffer swap function, we enter into a while loop waiting for this flag to be set. At the same time, the wl_display is polled to block the thread and wakeup if it receives any events from the compositor. This loop only breaks if enough time has passed or if the frame callback bool is received. In the near future, it is better to set whether or not frame a frame has been displayed in the presentation feedback. However as a first pass, doing it in the frame callback is more than good enough. The "downside" is that we render frames that aren't actually shown on screen when the player is hidden (it seems like wayland people don't like that). But who cares. Accurate timings are way more important. It's probably not too hard to add that behavior back in the player though.
2019-10-07 20:58:36 +00:00
struct ra_vk_ctx_params params = {
.check_visible = wayland_vk_check_visible,
wayland: use callback flag + poll for buffer swap The old way of using wayland in mpv relied on an external renderloop for semi-accurate timings. This had multiple issues though. Display sync would break whenever the window was hidden (since the frame callback stopped being executed) which was really annoying. Also the entire external renderloop logic was kind of fragile and didn't play well with mpv's internal structure (i.e. using presentation time in that old paradigm breaks stats.lua). Basically the problem is that swap buffers blocks on wayland which is crap whenever you hide the mpv window since it looks up the entire player. So you have to make swap buffers not block, but this has a different problem. Timings will be terrible if you use the unblocked swap buffers call. Based on some discussion in #wayland, the trick here is relatively simple and works well enough for our purposes. Instead we basically build a way to block with a timeout in the wayland buffer swap functions. A bool is set in the frame callback function that indicates whether or not mpv is waiting for a frame to be displayed. In the actual buffer swap function, we enter into a while loop waiting for this flag to be set. At the same time, the wl_display is polled to block the thread and wakeup if it receives any events from the compositor. This loop only breaks if enough time has passed or if the frame callback bool is received. In the near future, it is better to set whether or not frame a frame has been displayed in the presentation feedback. However as a first pass, doing it in the frame callback is more than good enough. The "downside" is that we render frames that aren't actually shown on screen when the player is hidden (it seems like wayland people don't like that). But who cares. Accurate timings are way more important. It's probably not too hard to add that behavior back in the player though.
2019-10-07 20:58:36 +00:00
.swap_buffers = wayland_vk_swap_buffers,
.get_vsync = wayland_vk_get_vsync,
wayland: use callback flag + poll for buffer swap The old way of using wayland in mpv relied on an external renderloop for semi-accurate timings. This had multiple issues though. Display sync would break whenever the window was hidden (since the frame callback stopped being executed) which was really annoying. Also the entire external renderloop logic was kind of fragile and didn't play well with mpv's internal structure (i.e. using presentation time in that old paradigm breaks stats.lua). Basically the problem is that swap buffers blocks on wayland which is crap whenever you hide the mpv window since it looks up the entire player. So you have to make swap buffers not block, but this has a different problem. Timings will be terrible if you use the unblocked swap buffers call. Based on some discussion in #wayland, the trick here is relatively simple and works well enough for our purposes. Instead we basically build a way to block with a timeout in the wayland buffer swap functions. A bool is set in the frame callback function that indicates whether or not mpv is waiting for a frame to be displayed. In the actual buffer swap function, we enter into a while loop waiting for this flag to be set. At the same time, the wl_display is polled to block the thread and wakeup if it receives any events from the compositor. This loop only breaks if enough time has passed or if the frame callback bool is received. In the near future, it is better to set whether or not frame a frame has been displayed in the presentation feedback. However as a first pass, doing it in the frame callback is more than good enough. The "downside" is that we render frames that aren't actually shown on screen when the player is hidden (it seems like wayland people don't like that). But who cares. Accurate timings are way more important. It's probably not too hard to add that behavior back in the player though.
2019-10-07 20:58:36 +00:00
};
VkInstance inst = vk->vkinst->instance;
VkResult res = vkCreateWaylandSurfaceKHR(inst, &wlinfo, NULL, &vk->surface);
if (res != VK_SUCCESS) {
MP_MSG(ctx, msgl, "Failed creating Wayland surface\n");
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 */
wayland: use callback flag + poll for buffer swap The old way of using wayland in mpv relied on an external renderloop for semi-accurate timings. This had multiple issues though. Display sync would break whenever the window was hidden (since the frame callback stopped being executed) which was really annoying. Also the entire external renderloop logic was kind of fragile and didn't play well with mpv's internal structure (i.e. using presentation time in that old paradigm breaks stats.lua). Basically the problem is that swap buffers blocks on wayland which is crap whenever you hide the mpv window since it looks up the entire player. So you have to make swap buffers not block, but this has a different problem. Timings will be terrible if you use the unblocked swap buffers call. Based on some discussion in #wayland, the trick here is relatively simple and works well enough for our purposes. Instead we basically build a way to block with a timeout in the wayland buffer swap functions. A bool is set in the frame callback function that indicates whether or not mpv is waiting for a frame to be displayed. In the actual buffer swap function, we enter into a while loop waiting for this flag to be set. At the same time, the wl_display is polled to block the thread and wakeup if it receives any events from the compositor. This loop only breaks if enough time has passed or if the frame callback bool is received. In the near future, it is better to set whether or not frame a frame has been displayed in the presentation feedback. However as a first pass, doing it in the frame callback is more than good enough. The "downside" is that we render frames that aren't actually shown on screen when the player is hidden (it seems like wayland people don't like that). But who cares. Accurate timings are way more important. It's probably not too hard to add that behavior back in the player though.
2019-10-07 20:58:36 +00:00
if (!ra_vk_ctx_init(ctx, vk, params, VK_PRESENT_MODE_MAILBOX_KHR))
goto error;
ra_add_native_resource(ctx->ra, "wl", ctx->vo->wl->display);
return true;
error:
wayland_vk_uninit(ctx);
return false;
}
static bool resize(struct ra_ctx *ctx)
{
struct vo_wayland_state *wl = ctx->vo->wl;
MP_VERBOSE(wl, "Handling resize on the vk side\n");
const int32_t width = mp_rect_w(wl->geometry);
const int32_t height = mp_rect_h(wl->geometry);
vo_wayland_set_opaque_region(wl, ctx->opts.want_alpha);
return ra_vk_ctx_resize(ctx, width, height);
}
static bool wayland_vk_reconfig(struct ra_ctx *ctx)
{
return vo_wayland_reconfig(ctx->vo);
}
static int wayland_vk_control(struct ra_ctx *ctx, int *events, int request, void *arg)
{
int ret = vo_wayland_control(ctx->vo, events, request, arg);
if (*events & VO_EVENT_RESIZE) {
if (!resize(ctx))
return VO_ERROR;
}
return ret;
}
static void wayland_vk_wakeup(struct ra_ctx *ctx)
{
vo_wayland_wakeup(ctx->vo);
}
static void wayland_vk_wait_events(struct ra_ctx *ctx, int64_t until_time_us)
{
vo_wayland_wait_events(ctx->vo, until_time_us);
}
static void wayland_vk_update_render_opts(struct ra_ctx *ctx)
{
struct vo_wayland_state *wl = ctx->vo->wl;
vo_wayland_set_opaque_region(wl, ctx->opts.want_alpha);
wl_surface_commit(wl->surface);
}
const struct ra_ctx_fns ra_ctx_vulkan_wayland = {
.type = "vulkan",
.name = "waylandvk",
.reconfig = wayland_vk_reconfig,
.control = wayland_vk_control,
.wakeup = wayland_vk_wakeup,
.wait_events = wayland_vk_wait_events,
.update_render_opts = wayland_vk_update_render_opts,
.init = wayland_vk_init,
.uninit = wayland_vk_uninit,
};