diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackScrollLayout.java b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackScrollLayout.java
index 34929f261b8b4..880e55847a461 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackScrollLayout.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackScrollLayout.java
@@ -407,6 +407,7 @@ public class NotificationStackScrollLayout extends ViewGroup implements Dumpable
     private boolean mBackwardScrollable;
     private NotificationShelf mShelf;
     private int mMaxDisplayedNotifications = -1;
+    private float mKeyguardBottomPadding = -1;
     private int mStatusBarHeight;
     private int mMinInteractionHeight;
     private final Rect mClipRect = new Rect();
@@ -742,6 +743,16 @@ public class NotificationStackScrollLayout extends ViewGroup implements Dumpable
             mDebugPaint.setColor(Color.YELLOW);
             canvas.drawLine(0, y, getWidth(), y, mDebugPaint);
 
+            y = (int) mMaxLayoutHeight;
+            mDebugPaint.setColor(Color.MAGENTA);
+            canvas.drawLine(0, y, getWidth(), y, mDebugPaint);
+
+            if (mKeyguardBottomPadding >= 0) {
+                y = getHeight() - (int) mKeyguardBottomPadding;
+                mDebugPaint.setColor(Color.GRAY);
+                canvas.drawLine(0, y, getWidth(), y, mDebugPaint);
+            }
+
             y = getHeight() - getEmptyBottomMargin();
             mDebugPaint.setColor(Color.GREEN);
             canvas.drawLine(0, y, getWidth(), y, mDebugPaint);
@@ -4784,6 +4795,16 @@ public class NotificationStackScrollLayout extends ViewGroup implements Dumpable
         }
     }
 
+    /**
+     * This is used for debugging only; it will be used to draw the otherwise invisible line which
+     * NotificationPanelViewController treats as the bottom when calculating how many notifications
+     * appear on the keyguard.
+     * Setting a negative number will disable rendering this line.
+     */
+    public void setKeyguardBottomPadding(float keyguardBottomPadding) {
+        mKeyguardBottomPadding = keyguardBottomPadding;
+    }
+
     @ShadeViewRefactor(RefactorComponent.SHADE_VIEW)
     public void setShouldShowShelfOnly(boolean shouldShowShelfOnly) {
         mShouldShowShelfOnly = shouldShowShelfOnly;
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackScrollLayoutController.java b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackScrollLayoutController.java
index 417418af477f8..a865c3a5e3f89 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackScrollLayoutController.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationStackScrollLayoutController.java
@@ -1218,6 +1218,16 @@ public class NotificationStackScrollLayoutController {
         mNotificationListContainer.setMaxDisplayedNotifications(maxNotifications);
     }
 
+    /**
+     * This is used for debugging only; it will be used to draw the otherwise invisible line which
+     * NotificationPanelViewController treats as the bottom when calculating how many notifications
+     * appear on the keyguard.
+     * Setting a negative number will disable rendering this line.
+     */
+    public void setKeyguardBottomPadding(float keyguardBottomPadding) {
+        mView.setKeyguardBottomPadding(keyguardBottomPadding);
+    }
+
     public RemoteInputController.Delegate createDelegate() {
         return new RemoteInputController.Delegate() {
             public void setRemoteInputActive(NotificationEntry entry,
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelViewController.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelViewController.java
index 2f4b036be4811..66d5960f7be00 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelViewController.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelViewController.java
@@ -340,6 +340,8 @@ public class NotificationPanelViewController extends PanelViewController {
     private final SplitShadeHeaderController mSplitShadeHeaderController;
     private final RecordingController mRecordingController;
     private boolean mShouldUseSplitNotificationShade;
+    // The bottom padding reserved for elements of the keyguard measuring notifications
+    private float mKeyguardNotificationBottomPadding;
     // Current max allowed keyguard notifications determined by measuring the panel
     private int mMaxAllowedKeyguardNotifications;
 
@@ -1215,9 +1217,12 @@ public class NotificationPanelViewController extends PanelViewController {
         if (mKeyguardShowing && !mKeyguardBypassController.getBypassEnabled()) {
             mNotificationStackScrollLayoutController.setMaxDisplayedNotifications(
                     mMaxAllowedKeyguardNotifications);
+            mNotificationStackScrollLayoutController.setKeyguardBottomPadding(
+                    mKeyguardNotificationBottomPadding);
         } else {
             // no max when not on the keyguard
             mNotificationStackScrollLayoutController.setMaxDisplayedNotifications(-1);
+            mNotificationStackScrollLayoutController.setKeyguardBottomPadding(-1f);
         }
     }
 
@@ -1422,6 +1427,7 @@ public class NotificationPanelViewController extends PanelViewController {
 
         float bottomPadding = Math.max(mIndicationBottomPadding, mAmbientIndicationBottomPadding);
         bottomPadding = Math.max(lockIconPadding, bottomPadding);
+        mKeyguardNotificationBottomPadding = bottomPadding;
 
         float availableSpace =
                 mNotificationStackScrollLayoutController.getHeight()