By popular request: Change the invalid device number and add a comment

explaining the reasons behind it. Oh well, at least the commit count raises...


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@30644 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/add-ons/kernel/bus_managers/ata/ATAChannel.cpp

@@ -293,7 +293,11 @@ ATAChannel::SelectedDevice()
 	ata_task_file taskFile;
 	if (_ReadRegs(&taskFile, ATA_MASK_DEVICE_HEAD) != B_OK) {
 		TRACE_ERROR("reading register failed when detecting selected device\n");
-		return 2;
+		// Return an invalid device number so that the
+		// SelectedDevice() == "expected device" check fails.
+		// Due to the device number being a bit, we can't really get values
+		// other than 0 and 1, so anything >= 2 can be regarded as invalid.
+		return 234;
 	}
 
 	return taskFile.lba.device;