diff --git a/include/hardware/hwcomposer2.h b/include/hardware/hwcomposer2.h
index 2a0dd73..7db2aba 100644
--- a/include/hardware/hwcomposer2.h
+++ b/include/hardware/hwcomposer2.h
@@ -73,6 +73,7 @@
     HWC2_CALLBACK_HOTPLUG = 1,
     HWC2_CALLBACK_REFRESH = 2,
     HWC2_CALLBACK_VSYNC = 3,
+    HWC2_CALLBACK_VSYNC_2_4 = 4,
 } hwc2_callback_descriptor_t;
 
 /* Optional capabilities which may be supported by some devices. The particular
@@ -220,6 +221,8 @@
     HWC2_ERROR_NO_RESOURCES,
     HWC2_ERROR_NOT_VALIDATED,
     HWC2_ERROR_UNSUPPORTED,
+    HWC2_ERROR_BAD_VSYNC_PERIOD,
+    HWC2_ERROR_SEAMLESS_NOT_POSSIBLE,
 } hwc2_error_t;
 
 /* Function descriptors for use with getFunction */
@@ -291,6 +294,9 @@
 
     // composer 2.4
     HWC2_FUNCTION_GET_DISPLAY_CONNECTION_TYPE,
+    HWC2_FUNCTION_GET_SUPPORTED_DISPLAY_VSYNC_PERIODS,
+    HWC2_FUNCTION_GET_DISPLAY_VSYNC_PERIOD,
+    HWC2_FUNCTION_SET_ACTIVE_CONFIG_AND_VSYNC_PERIOD,
 } hwc2_function_descriptor_t;
 
 /* Layer requests returned from getDisplayRequests */
@@ -537,6 +543,8 @@
         case HWC2_ERROR_NO_RESOURCES: return "NoResources";
         case HWC2_ERROR_NOT_VALIDATED: return "NotValidated";
         case HWC2_ERROR_UNSUPPORTED: return "Unsupported";
+        case HWC2_ERROR_BAD_VSYNC_PERIOD: return "BadVsyncPeriod";
+        case HWC2_ERROR_SEAMLESS_NOT_POSSIBLE: return "SeamlessNotPossible";
         default: return "Unknown";
     }
 }
@@ -622,6 +630,9 @@
 
         // composer 2.4
         case HWC2_FUNCTION_GET_DISPLAY_CONNECTION_TYPE: return "GetDisplayConnectionType";
+        case HWC2_FUNCTION_GET_SUPPORTED_DISPLAY_VSYNC_PERIODS: return "getSupportedDisplayVsyncPeriods";
+        case HWC2_FUNCTION_GET_DISPLAY_VSYNC_PERIOD: return "getDisplayVsyncPeriod";
+        case HWC2_FUNCTION_SET_ACTIVE_CONFIG_AND_VSYNC_PERIOD: return "setActiveConfigAndVsyncPeriod";
 
         default: return "Unknown";
     }
@@ -745,6 +756,7 @@
     Hotplug = HWC2_CALLBACK_HOTPLUG,
     Refresh = HWC2_CALLBACK_REFRESH,
     Vsync = HWC2_CALLBACK_VSYNC,
+    Vsync_2_4 = HWC2_CALLBACK_VSYNC_2_4,
 };
 TO_STRING(hwc2_callback_descriptor_t, Callback, getCallbackDescriptorName)
 
@@ -804,6 +816,8 @@
     NoResources = HWC2_ERROR_NO_RESOURCES,
     NotValidated = HWC2_ERROR_NOT_VALIDATED,
     Unsupported = HWC2_ERROR_UNSUPPORTED,
+    BadVsyncPeriod = HWC2_ERROR_BAD_VSYNC_PERIOD,
+    SeamlessNotPossible = HWC2_ERROR_SEAMLESS_NOT_POSSIBLE,
 };
 TO_STRING(hwc2_error_t, Error, getErrorName)
 
@@ -875,6 +889,10 @@
 
     // composer 2.4
     GetDisplayConnectionType = HWC2_FUNCTION_GET_DISPLAY_CONNECTION_TYPE,
+    getSupportedDisplayVsyncPeriods = HWC2_FUNCTION_GET_SUPPORTED_DISPLAY_VSYNC_PERIODS,
+    getDisplayVsyncPeriod = HWC2_FUNCTION_GET_DISPLAY_VSYNC_PERIOD,
+    setActiveConfigAndVsyncPeriod = HWC2_FUNCTION_SET_ACTIVE_CONFIG_AND_VSYNC_PERIOD,
+
 };
 TO_STRING(hwc2_function_descriptor_t, FunctionDescriptor,
         getFunctionDescriptorName)
@@ -934,6 +952,7 @@
 typedef uint32_t hwc2_config_t;
 typedef uint64_t hwc2_display_t;
 typedef uint64_t hwc2_layer_t;
+typedef uint32_t hwc2_vsync_period_t;
 
 /*
  * Device Struct
@@ -1060,6 +1079,28 @@
 typedef void (*HWC2_PFN_VSYNC)(hwc2_callback_data_t callbackData,
         hwc2_display_t display, int64_t timestamp);
 
+/* vsync_2_4(..., display, timestamp, vsyncPeriodNanos)
+ * Descriptor: HWC2_CALLBACK_VSYNC_2_4
+ * Required for HWC2 devices for composer 2.4
+ *
+ * Notifies the client that a vsync event has occurred. This callback must
+ * only be triggered when vsync is enabled for this display (through
+ * setVsyncEnabled).
+ *
+ * This callback should be triggered from a thread of at least
+ * HAL_PRIORITY_URGENT_DISPLAY with as little latency as possible, typically
+ * less than 0.5 ms. This thread is guaranteed not to call back into the device.
+ *
+ * Parameters:
+ *   display - the display which has received a vsync event
+ *   timestamp - the CLOCK_MONOTONIC time at which the vsync event occurred, in
+ *       nanoseconds
+ *   vsyncPeriodNanos - the display vsync period in nanoseconds i.e. the next onVsync2_4 is
+ *   expected to be called vsyncPeriod nanoseconds after this call.
+ */
+typedef void (*HWC2_PFN_VSYNC_2_4)(hwc2_callback_data_t callbackData,
+        hwc2_display_t display, int64_t timestamp, hwc2_vsync_period_t vsyncPeriodNanos);
+
 /*
  * Device Functions
  *
@@ -2773,6 +2814,92 @@
         hwc2_device_t* device, hwc2_display_t display,
         uint32_t* /*hwc2_display_connection_type_t*/ outType);
 
+/* getSupportedDisplayVsyncPeriods(..., outNumVsyncPeriods, outVsyncPeriods)
+ * Descriptor: HWC2_FUNCTION_GET_SUPPORTED_DISPLAY_VSYNC_PERIODS
+ * Required for HWC2 devices for composer 2.4
+ *
+ * Returns a array of supported vsync periods the display can refresh at a given configuration.
+ *
+ * outVsyncPeriods may be NULL to retrieve the number of elements which will be returned.
+ *
+ * Parameters:
+ *   outNumVsyncPeriods - if outVsyncPeriods was NULL, the number of vsync periods which
+ *       would have been returned; if outVsyncPeriods was not NULL, the number of
+ *       vsync periods returned, which must not exceed the value stored in
+ *       outNumVsyncPeriods prior to the call; pointer will be non-NULL
+ *   outVsyncPeriods - an array of vsync periods
+ *
+ * Returns HWC2_ERROR_NONE or one of the following errors:
+ *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
+ *   HWC2_ERROR_BAD_CONFIG - the configuration handle passed in is not valid for
+ *       this display
+ */
+typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_SUPPORTED_DISPLAY_VSYNC_PERIODS)(
+        hwc2_device_t* device, hwc2_display_t display, hwc2_config_t config,
+        uint32_t* outNumVsyncPeriods, hwc2_vsync_period_t* outVsyncPeriods);
+
+/* getDisplayVsyncPeriod(..., outVsyncPeriods)
+ * Descriptor: HWC2_FUNCTION_GET_DISPLAY_VSYNC_PERIOD
+ * Required for HWC2 devices for composer 2.4
+ *
+ * Retrieves which vsync period the display is currently using.
+ *
+ * If no display configuration is currently active, this function must
+ * return BAD_CONFIG. If a vsync period is about to change due to a
+ * setActiveConfigAndVsyncPeriod call, this function must return the current vsync period
+ * until the change has taken place.
+ *
+ * Parameters:
+ *     outVsyncPeriod - the current vsync period of the display.
+ *
+ * Returns HWC2_ERROR_NONE or one of the following errors:
+ *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in
+ *   HWC2_ERROR_BAD_CONFIG - no configuration is currently active
+ */
+typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_GET_DISPLAY_VSYNC_PERIOD)(
+        hwc2_device_t* device, hwc2_display_t display, hwc2_vsync_period_t* outVsyncPeriod);
+
+/* setActiveConfigAndVsyncPeriod(..., config, vsyncPeriodNanos,
+ *                               vsyncPeriodChangeConstraints, outNewVsyncAppliedTime)
+ * Descriptor: HWC2_FUNCTION_SET_ACTIVE_CONFIG_AND_VSYNC_PERIOD
+ * Required for HWC2 devices for composer 2.4
+ *
+ * Sets the active configuration and the refresh rate for this display.
+ * If the config is the same as the current config, only the vsync period shall change.
+ * Upon returning, the given display configuration, except vsync period, must be active and
+ * remain so until either this function is called again or the display is disconnected.
+ * When the display starts to refresh at the new vsync period, onVsync_2_4 callback must be
+ * called with the new vsync period.
+ *
+ * Parameters:
+ *     config - the new display configuration.
+ *     vsyncPeriodNanos - the new display vsync period.
+ *     vsyncPeriodChangeConstraints - constraints required for changing vsync period:
+ *                                    desiredTimeNanos - the time in CLOCK_MONOTONIC after
+ *                                                       which the vsync period may change
+ *                                                       (i.e., the vsync period must not change
+ *                                                       before this time).
+ *                                    seamlessRequired - if true, requires that the vsync period
+ *                                                       change must happen seamlessly without
+ *                                                       a noticeable visual artifact.
+ *     outNewVsyncAppliedTime - the time in CLOCK_MONOTONIC when the new display will start to
+ *                              refresh at the new vsync period.
+ *
+ * Returns HWC2_ERROR_NONE or one of the following errors:
+ *   HWC2_ERROR_BAD_DISPLAY - an invalid display handle was passed in.
+ *   HWC2_ERROR_BAD_CONFIG - an invalid configuration handle passed in.
+ *   HWC2_ERROR_BAD_VSYNC_PERIOD - an invalid vsync period is passed in.
+ *   HWC2_ERROR_SEAMLESS_NOT_POSSIBLE - when seamlessRequired was true but the display cannot
+ *                                      achieve the vsync period change without a noticeable
+ *                                      visual artifact.
+ */
+typedef int32_t /*hwc2_error_t*/ (*HWC2_PFN_SET_ACTIVE_CONFIG_AND_VSYNC_PERIOD)(
+        hwc2_device_t* device, hwc2_display_t display, hwc2_config_t config,
+        hwc2_vsync_period_t vsyncPeriodNanos,
+        hwc_vsync_period_change_constraints_t* vsyncPeriodChangeConstraints,
+        int64_t* outNewVsyncAppliedTime);
+
+
 __END_DECLS
 
 #endif