From aa0c2157e888f24873a0f1fca396e4fce0f79c84 Mon Sep 17 00:00:00 2001
From: Vaxry <vaxry@vaxry.net>
Date: Tue, 25 Jun 2024 20:30:00 +0200
Subject: [PATCH] drm: adjust drmfb storage

---
 include/aquamarine/backend/DRM.hpp |  4 ++--
 src/backend/drm/DRM.cpp            | 21 +++++++++++++--------
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/include/aquamarine/backend/DRM.hpp b/include/aquamarine/backend/DRM.hpp
index 2f1f4ae..02dddba 100644
--- a/include/aquamarine/backend/DRM.hpp
+++ b/include/aquamarine/backend/DRM.hpp
@@ -54,7 +54,7 @@ namespace Aquamarine {
     struct SDRMLayer {
         // we expect the consumers to use double-buffering, so we keep the 2 last FBs around. If any of these goes out of
         // scope, the DRM FB will be destroyed, but the IBuffer will stay, as long as it's ref'd somewhere.
-        Hyprutils::Memory::CSharedPointer<CDRMFB>    front /* currently displaying */, back;
+        Hyprutils::Memory::CSharedPointer<CDRMFB>    front /* currently displaying */, back /* submitted */, last /* keep just in case */;
         Hyprutils::Memory::CWeakPointer<CDRMBackend> backend;
     };
 
@@ -65,7 +65,7 @@ namespace Aquamarine {
         uint32_t                                     id        = 0;
         uint32_t                                     initialID = 0;
 
-        Hyprutils::Memory::CSharedPointer<CDRMFB>    front /* currently displaying */, back /* submitted */;
+        Hyprutils::Memory::CSharedPointer<CDRMFB>    front /* currently displaying */, back /* submitted */, last /* keep just in case */;
         Hyprutils::Memory::CWeakPointer<CDRMBackend> backend;
         Hyprutils::Memory::CWeakPointer<SDRMPlane>   self;
         std::vector<SDRMFormat>                      formats;
diff --git a/src/backend/drm/DRM.cpp b/src/backend/drm/DRM.cpp
index 7eafd5f..596ce21 100644
--- a/src/backend/drm/DRM.cpp
+++ b/src/backend/drm/DRM.cpp
@@ -894,12 +894,9 @@ bool Aquamarine::SDRMConnector::commitState(const SDRMConnectorCommitData& data)
 }
 
 void Aquamarine::SDRMConnector::applyCommit(const SDRMConnectorCommitData& data) {
-    crtc->primary->back  = crtc->primary->front;
-    crtc->primary->front = data.mainFB;
-    if (crtc->cursor) {
-        crtc->cursor->back  = crtc->cursor->front;
-        crtc->cursor->front = data.cursorFB;
-    }
+    crtc->primary->back = data.mainFB;
+    if (crtc->cursor)
+        crtc->cursor->back = data.cursorFB;
 
     pendingCursorFB.reset();
 
@@ -912,7 +909,12 @@ void Aquamarine::SDRMConnector::rollbackCommit(const SDRMConnectorCommitData& da
 }
 
 void Aquamarine::SDRMConnector::onPresent() {
-    ;
+    crtc->primary->last  = crtc->primary->front;
+    crtc->primary->front = crtc->primary->back;
+    if (crtc->cursor) {
+        crtc->cursor->last  = crtc->cursor->front;
+        crtc->cursor->front = crtc->cursor->back;
+    }
 }
 
 Aquamarine::CDRMOutput::~CDRMOutput() {
@@ -1004,11 +1006,14 @@ bool Aquamarine::CDRMOutput::commitState(bool onlyTest) {
         auto       buf = STATE.buffer;
         // try to find the buffer in its layer
         if (connector->crtc->primary->back && connector->crtc->primary->back->buffer == buf) {
-            backend->backend->log(AQ_LOG_TRACE, "drm: CRTC's back buffer matches committed :D");
+            backend->backend->log(AQ_LOG_TRACE, "drm: CRTC's back buffer matches committed");
             drmFB = connector->crtc->primary->back;
         } else if (connector->crtc->primary->front && connector->crtc->primary->front->buffer == buf) {
             backend->backend->log(AQ_LOG_TRACE, "drm: CRTC's front buffer matches committed");
             drmFB = connector->crtc->primary->front;
+        } else if (connector->crtc->primary->last && connector->crtc->primary->last->buffer == buf) {
+            backend->backend->log(AQ_LOG_TRACE, "drm: CRTC's last buffer matches committed :D"); // best case scenario and what is expected
+            drmFB = connector->crtc->primary->last;
         }
 
         if (!drmFB)