renderer: Explicit sync fixes (#7151)

Enables explicit sync by default for most platforms

`misc:no_direct_scanout` -> `render:direct_scanout`

src/helpers/Monitor.cpp

@@ -1,6 +1,8 @@
 #include "Monitor.hpp"
 #include "MiscFunctions.hpp"
 #include "math/Math.hpp"
+#include "sync/SyncReleaser.hpp"
+#include "ScopeGuard.hpp"
 #include "../Compositor.hpp"
 #include "../config/ConfigValue.hpp"
 #include "../protocols/GammaControl.hpp"
@@ -8,6 +10,7 @@
 #include "../protocols/LayerShell.hpp"
 #include "../protocols/PresentationTime.hpp"
 #include "../protocols/DRMLease.hpp"
+#include "../protocols/DRMSyncobj.hpp"
 #include "../protocols/core/Output.hpp"
 #include "../managers/PointerManager.hpp"
 #include "../protocols/core/Compositor.hpp"
@@ -77,6 +80,7 @@ void CMonitor::onConnect(bool noRule) {
     tearingState.canTear = output->getBackend()->type() == Aquamarine::AQ_BACKEND_DRM;
 
     if (m_bEnabled) {
+        output->state->resetExplicitFences();
         output->state->setEnabled(true);
         state.commit();
         return;
@@ -101,6 +105,7 @@ void CMonitor::onConnect(bool noRule) {
     // if it's disabled, disable and ignore
     if (monitorRule.disabled) {
 
+        output->state->resetExplicitFences();
         output->state->setEnabled(false);
 
         if (!state.commit())
@@ -137,6 +142,7 @@ void CMonitor::onConnect(bool noRule) {
 
     m_bEnabled = true;
 
+    output->state->resetExplicitFences();
     output->state->setEnabled(true);
 
     // set mode, also applies
@@ -300,6 +306,7 @@ void CMonitor::onDisconnect(bool destroy) {
         activeWorkspace->m_bVisible = false;
     activeWorkspace.reset();
 
+    output->state->resetExplicitFences();
     output->state->setEnabled(false);
 
     if (!state.commit())
@@ -808,28 +815,77 @@ bool CMonitor::attemptDirectScanout() {
     if (!PSURFACE->current.buffer || !PSURFACE->current.texture || !PSURFACE->current.texture->m_pEglImage /* dmabuf */)
         return false;
 
+    Debug::log(TRACE, "attemptDirectScanout: surface {:x} passed, will attempt", (uintptr_t)PSURFACE.get());
+
     // FIXME: make sure the buffer actually follows the available scanout dmabuf formats
     // and comes from the appropriate device. This may implode on multi-gpu!!
     output->state->setBuffer(PSURFACE->current.buffer->buffer.lock());
     output->state->setPresentationMode(tearingState.activelyTearing ? Aquamarine::eOutputPresentationMode::AQ_OUTPUT_PRESENTATION_IMMEDIATE :
                                                                       Aquamarine::eOutputPresentationMode::AQ_OUTPUT_PRESENTATION_VSYNC);
 
-    if (!state.test())
+    if (!state.test()) {
+        Debug::log(TRACE, "attemptDirectScanout: failed basic test");
         return false;
+    }
+
+    auto explicitOptions = g_pHyprRenderer->getExplicitSyncSettings();
+
+    // wait for the explicit fence if present, and if kms explicit is allowed
+    bool DOEXPLICIT = PSURFACE->syncobj && PSURFACE->syncobj->current.acquireTimeline && PSURFACE->syncobj->current.acquireTimeline->timeline && explicitOptions.explicitKMSEnabled;
+    int  explicitWaitFD = -1;
+    if (DOEXPLICIT) {
+        explicitWaitFD = PSURFACE->syncobj->current.acquireTimeline->timeline->exportAsSyncFileFD(PSURFACE->syncobj->current.acquirePoint);
+        if (explicitWaitFD < 0)
+            Debug::log(TRACE, "attemptDirectScanout: failed to acquire an explicit wait fd");
+    }
+    DOEXPLICIT = DOEXPLICIT && explicitWaitFD >= 0;
+
+    auto     cleanup = CScopeGuard([explicitWaitFD, this]() {
+        output->state->resetExplicitFences();
+        if (explicitWaitFD >= 0)
+            close(explicitWaitFD);
+    });
 
     timespec now;
     clock_gettime(CLOCK_MONOTONIC, &now);
-    Debug::log(TRACE, "presentFeedback for DS");
-    PSURFACE->presentFeedback(&now, this, true);
+    PSURFACE->presentFeedback(&now, this);
 
     output->state->addDamage(CBox{{}, vecPixelSize});
+    output->state->resetExplicitFences();
 
-    if (state.commit()) {
+    if (DOEXPLICIT) {
+        Debug::log(TRACE, "attemptDirectScanout: setting IN_FENCE for aq to {}", explicitWaitFD);
+        output->state->setExplicitInFence(explicitWaitFD);
+    }
+
+    bool ok = output->commit();
+
+    if (!ok && DOEXPLICIT) {
+        Debug::log(TRACE, "attemptDirectScanout: EXPLICIT SYNC FAILED: commit() returned false. Resetting fences and retrying, might result in glitches.");
+        output->state->resetExplicitFences();
+
+        ok = output->commit();
+    }
+
+    if (ok) {
         if (lastScanout.expired()) {
             lastScanout = PCANDIDATE;
             Debug::log(LOG, "Entered a direct scanout to {:x}: \"{}\"", (uintptr_t)PCANDIDATE.get(), PCANDIDATE->m_szTitle);
         }
+
+        // delay explicit sync feedback until kms release of the buffer
+        if (DOEXPLICIT) {
+            Debug::log(TRACE, "attemptDirectScanout: Delaying explicit sync release feedback until kms release");
+            PSURFACE->current.buffer->releaser->drop();
+
+            PSURFACE->current.buffer->buffer->hlEvents.backendRelease2 = PSURFACE->current.buffer->buffer->events.backendRelease.registerListener([PSURFACE](std::any d) {
+                const bool DOEXPLICIT = PSURFACE->syncobj && PSURFACE->syncobj->current.releaseTimeline && PSURFACE->syncobj->current.releaseTimeline->timeline;
+                if (DOEXPLICIT)
+                    PSURFACE->syncobj->current.releaseTimeline->timeline->signal(PSURFACE->syncobj->current.releasePoint);
+            });
+        }
     } else {
+        Debug::log(TRACE, "attemptDirectScanout: failed to scanout surface");
         lastScanout.reset();
         return false;
     }

src/helpers/Monitor.hpp

@@ -121,8 +121,7 @@ class CMonitor {
     // explicit sync
     SP<CSyncTimeline> inTimeline;
     SP<CSyncTimeline> outTimeline;
-    uint64_t          lastWaitPoint = 0;
-    uint64_t          commitSeq     = 0;
+    uint64_t          commitSeq = 0;
 
     WP<CMonitor>      self;
 

src/helpers/ScopeGuard.cpp

@@ -0,0 +1,10 @@
+#include "ScopeGuard.hpp"
+
+CScopeGuard::CScopeGuard(const std::function<void()>& fn_) : fn(fn_) {
+    ;
+}
+
+CScopeGuard::~CScopeGuard() {
+    if (fn)
+        fn();
+}

src/helpers/ScopeGuard.hpp

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <functional>
+
+// calls a function when it goes out of scope
+class CScopeGuard {
+  public:
+    CScopeGuard(const std::function<void()>& fn_);
+    ~CScopeGuard();
+
+  private:
+    std::function<void()> fn;
+};

src/helpers/sync/SyncReleaser.cpp

@@ -0,0 +1,25 @@
+#include "SyncReleaser.hpp"
+#include "SyncTimeline.hpp"
+#include "../../render/OpenGL.hpp"
+
+CSyncReleaser::CSyncReleaser(WP<CSyncTimeline> timeline_, uint64_t point_) : timeline(timeline_), point(point_) {
+    ;
+}
+
+CSyncReleaser::~CSyncReleaser() {
+    if (timeline.expired())
+        return;
+
+    if (sync)
+        timeline->importFromSyncFileFD(point, sync->fd());
+    else
+        timeline->signal(point);
+}
+
+void CSyncReleaser::addReleaseSync(SP<CEGLSync> sync_) {
+    sync = sync_;
+}
+
+void CSyncReleaser::drop() {
+    timeline.reset();
+}

src/helpers/sync/SyncReleaser.hpp

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <cstdint>
+#include <optional>
+#include <vector>
+#include <functional>
+#include "../memory/Memory.hpp"
+
+/*
+    A helper (inspired by KDE's KWin) that will release the timeline point in the dtor
+*/
+
+class CSyncTimeline;
+class CEGLSync;
+
+class CSyncReleaser {
+  public:
+    CSyncReleaser(WP<CSyncTimeline> timeline_, uint64_t point_);
+    ~CSyncReleaser();
+
+    // drops the releaser, will never signal anymore
+    void drop();
+
+    // wait for this gpu job to finish before releasing
+    void addReleaseSync(SP<CEGLSync> sync);
+
+  private:
+    WP<CSyncTimeline> timeline;
+    uint64_t          point = 0;
+    SP<CEGLSync>      sync;
+};

src/helpers/sync/SyncTimeline.cpp

@@ -188,3 +188,8 @@ bool CSyncTimeline::transfer(SP<CSyncTimeline> from, uint64_t fromPoint, uint64_
 
     return true;
 }
+
+void CSyncTimeline::signal(uint64_t point) {
+    if (drmSyncobjTimelineSignal(drmFD, &handle, &point, 1))
+        Debug::log(ERR, "CSyncTimeline::signal: drmSyncobjTimelineSignal failed");
+}

src/helpers/sync/SyncTimeline.hpp

@@ -35,6 +35,7 @@ class CSyncTimeline {
     int                 exportAsSyncFileFD(uint64_t src);
     bool                importFromSyncFileFD(uint64_t dst, int fd);
     bool                transfer(SP<CSyncTimeline> from, uint64_t fromPoint, uint64_t toPoint);
+    void                signal(uint64_t point);
 
     int                 drmFD  = -1;
     uint32_t            handle = 0;