From 87a233ab3fb2cf7652efba7c8760348f4fd04008 Mon Sep 17 00:00:00 2001
From: "Sijmen J. Mulder" <s.mulder@betabit.nl>
Date: Thu, 11 Oct 2018 23:00:03 +0200
Subject: [PATCH] Check for floating bus

Fixes #1056: Does not boot if there is no IDE Secondary Master
(VirtualBox)
---
 source/Cosmos.HAL2/BlockDevice/AtaPio.cs | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/source/Cosmos.HAL2/BlockDevice/AtaPio.cs b/source/Cosmos.HAL2/BlockDevice/AtaPio.cs
index 36bfda339b..028b4c42ce 100644
--- a/source/Cosmos.HAL2/BlockDevice/AtaPio.cs
+++ b/source/Cosmos.HAL2/BlockDevice/AtaPio.cs
@@ -163,6 +163,14 @@ public AtaPio(Core.IOGroup.ATA aIO, Ata.ControllerIdEnum aControllerId, Ata.BusP
 		public SpecLevel DiscoverDrive()
 		{
 			SelectDrive(0);
+
+			// Read status before sending command. If 0xFF, it's a floating
+			// bus (nothing connected)
+			if (IO.Status.Byte == 0xFF)
+			{
+				return SpecLevel.Null;
+			}
+
 			var xIdentifyStatus = SendCmd(Cmd.Identify, false);
 			// No drive found, go to next
 			if (xIdentifyStatus == Status.None)