sdm: Clear fb_id map if it exceeds the size limit

Clear the fb_id map of SDM HW layer, if it exceeds the size limit.
It is required for cases like pre-rotation where new buffer handles
are allocated and new unique handle ids are used on same HWC layer
for consecutive draw cycles involving device rotations.

CRs-Fixed: 2247747
Change-Id: Iec71c42572f589717ad8f5677f84ff16e0aaaf01

2 files changed, 6 insertions, 4 deletions

diff --git a/sdm/libs/core/drm/hw_device_drm.cpp b/sdm/libs/core/drm/hw_device_drm.cpp
index adb7b95d..aa318be3 100644
--- a/sdm/libs/core/drm/hw_device_drm.cpp
+++ b/sdm/libs/core/drm/hw_device_drm.cpp
@@ -300,9 +300,10 @@ void HWDeviceDRM::Registry::MapBufferToFbId(Layer* layer, LayerBuffer* buffer) {
   }
 
   uint64_t handle_id = buffer->handle_id;
+  bool legacy_path = !handle_id || disable_fbid_cache_;
 
-  if (!handle_id || disable_fbid_cache_) {
-    // Legacy: Remove & Create fb_id in each frame
+  if (legacy_path || (layer->buffer_map->buffer_map.size() > fbid_cache_limit_)) {
+    // Clear fb_id map in each frame in legacy path or if the map size exceeds limit.
     layer->buffer_map->buffer_map.clear();
   }
 
@@ -325,8 +326,8 @@ void HWDeviceDRM::Registry::MapOutputBufferToFbId(LayerBuffer *output_buffer) {
 
   uint64_t handle_id = output_buffer->handle_id;
 
-  if (!handle_id || disable_fbid_cache_) {
-    // Legacy: Remove & Create fb_id in each frame
+  if (!handle_id || disable_fbid_cache_ || (output_buffer_map_.size() > fbid_cache_limit_)) {
+    // Clear output buffer map in each frame in legacy path or if the map size exceeds limit.
     output_buffer_map_.clear();
   }
 
diff --git a/sdm/libs/core/drm/hw_device_drm.h b/sdm/libs/core/drm/hw_device_drm.h
index 203b6bb6..728b47c5 100644
--- a/sdm/libs/core/drm/hw_device_drm.h
+++ b/sdm/libs/core/drm/hw_device_drm.h
@@ -157,6 +157,7 @@ class HWDeviceDRM : public HWInterface {
     bool disable_fbid_cache_ = false;
     std::unordered_map<uint64_t, std::shared_ptr<LayerBufferObject>> output_buffer_map_ {};
     BufferAllocator *buffer_allocator_ = {};
+    const uint8_t fbid_cache_limit_ = 16;
   };
 
  protected: