drm: check syncobj timeline support before advertising protocol (#11117)

Prevents crashes on systems where DRM driver lacks syncobj timeline
support (e.g., Apple Silicon with Honeykrisp driver). Applications
like Zed and WezTerm would crash with 'Timeline failed importing'
when trying to use explicit sync.

Fixes #8158 #8803

---------

Co-authored-by: mvonarx <matthias.vonarx@sitrox.com>

Author: mavonarx

src/Compositor.cpp

@@ -73,6 +73,7 @@
 #include <sys/resource.h>
 #include <malloc.h>
 #include <unistd.h>
+#include <xf86drm.h>
 
 using namespace Hyprutils::String;
 using namespace Aquamarine;
@@ -167,6 +168,10 @@ void CCompositor::restoreNofile() {
         Debug::log(ERR, "Failed restoring NOFILE limits");
 }
 
+bool CCompositor::supportsDrmSyncobjTimeline() const {
+    return m_bDrmSyncobjTimelineSupported;
+}
+
 void CCompositor::setMallocThreshold() {
 #ifdef M_TRIM_THRESHOLD
     // The default is 128 pages,
@@ -354,6 +359,16 @@ void CCompositor::initServer(std::string socketName, int socketFd) {
     m_drmFD = m_aqBackend->drmFD();
     Debug::log(LOG, "Running on DRMFD: {}", m_drmFD);
 
+    if (m_drmFD >= 0) {
+        uint64_t cap                   = 0;
+        int      ret                   = drmGetCap(m_drmFD, DRM_CAP_SYNCOBJ_TIMELINE, &cap);
+        m_bDrmSyncobjTimelineSupported = (ret == 0 && cap != 0);
+        Debug::log(LOG, "DRM syncobj timeline support: {}", m_bDrmSyncobjTimelineSupported ? "yes" : "no");
+    } else {
+        m_bDrmSyncobjTimelineSupported = false;
+        Debug::log(LOG, "DRM syncobj timeline support: no (no DRM FD)");
+    }
+
     if (!socketName.empty() && socketFd != -1) {
         fcntl(socketFd, F_SETFD, FD_CLOEXEC);
         const auto RETVAL = wl_display_add_socket_fd(m_wlDisplay, socketFd);

src/Compositor.hpp

@@ -152,6 +152,7 @@ class CCompositor {
     NColorManagement::SImageDescription getPreferredImageDescription();
     bool                                shouldChangePreferredImageDescription();
 
+    bool                                supportsDrmSyncobjTimeline() const;
     std::string                         m_explicitConfigPath;
 
   private:
@@ -165,6 +166,8 @@ class CCompositor {
     void             removeLockFile();
     void             setMallocThreshold();
 
+    bool             m_bDrmSyncobjTimelineSupported = false;
+
     uint64_t         m_hyprlandPID    = 0;
     wl_event_source* m_critSigSource  = nullptr;
     rlimit           m_originalNofile = {};

src/helpers/sync/SyncTimeline.cpp

@@ -1,12 +1,16 @@
 #include "SyncTimeline.hpp"
 #include "../../defines.hpp"
 #include "../../managers/eventLoop/EventLoopManager.hpp"
+#include "../../Compositor.hpp"
 
 #include <xf86drm.h>
 #include <sys/eventfd.h>
 using namespace Hyprutils::OS;
 
 SP<CSyncTimeline> CSyncTimeline::create(int drmFD_) {
+    if (!g_pCompositor->supportsDrmSyncobjTimeline())
+        return nullptr;
+
     auto timeline     = SP<CSyncTimeline>(new CSyncTimeline);
     timeline->m_drmFD = drmFD_;
     timeline->m_self  = timeline;
@@ -20,6 +24,9 @@ SP<CSyncTimeline> CSyncTimeline::create(int drmFD_) {
 }
 
 SP<CSyncTimeline> CSyncTimeline::create(int drmFD_, CFileDescriptor&& drmSyncobjFD) {
+    if (!g_pCompositor->supportsDrmSyncobjTimeline())
+        return nullptr;
+
     auto timeline         = SP<CSyncTimeline>(new CSyncTimeline);
     timeline->m_drmFD     = drmFD_;
     timeline->m_syncobjFD = std::move(drmSyncobjFD);

src/managers/ProtocolManager.cpp

@@ -70,6 +70,7 @@
 #include "content-type-v1.hpp"
 
 #include <aquamarine/buffer/Buffer.hpp>
+#include <xf86drm.h>
 #include <aquamarine/backend/Backend.hpp>
 #include <hyprutils/memory/UniquePtr.hpp>
 
@@ -210,8 +211,13 @@ CProtocolManager::CProtocolManager() {
         else
             lease.reset();
 
-        if (g_pHyprOpenGL->m_exts.EGL_ANDROID_native_fence_sync_ext && !PROTO::sync)
-            PROTO::sync = makeUnique<CDRMSyncobjProtocol>(&wp_linux_drm_syncobj_manager_v1_interface, 1, "DRMSyncobj");
+        if (g_pHyprOpenGL->m_exts.EGL_ANDROID_native_fence_sync_ext && !PROTO::sync) {
+            if (g_pCompositor->supportsDrmSyncobjTimeline()) {
+                PROTO::sync = makeUnique<CDRMSyncobjProtocol>(&wp_linux_drm_syncobj_manager_v1_interface, 1, "DRMSyncobj");
+                Debug::log(LOG, "DRM Syncobj Timeline support detected, enabling explicit sync protocol");
+            } else
+                Debug::log(WARN, "DRM Syncobj Timeline not supported, skipping explicit sync protocol");
+        }
     }
 
     if (!g_pHyprOpenGL->getDRMFormats().empty()) {