Sadly, it isn't compliant with newer boards like the PCI-E Titanium version. To use incompliant cards under linux, you have to edit the driver's source code.

First, you need to know the subsystem ID of your card. In this case it is 0x0042.

chorse@aquila:~$ lspci -v
[...]
02:00.0 Audio device: Creative Labs [X-Fi Titanium series] EMU20k2 (rev 03)
	Subsystem: Creative Labs Device 0042
	Flags: bus master, fast devsel, latency 0, IRQ 19
	Memory at fcff0000 (64-bit, non-prefetchable) [size=64K]
	Memory at fcc00000 (64-bit, non-prefetchable) [size=2M]
	Memory at fb000000 (64-bit, non-prefetchable) [size=16M]
	Capabilities: <access denied>
	Kernel driver in use: CTALSA
	Kernel modules: ctxfi
[...]

Now enter the directory where you have extracted the driver's source code into. Open
ctdrv.h with a text editor.

/**
 * Copyright (C) 2008, Creative Technology Ltd. All Rights Reserved.
 *
 * This source file is released under GPL v2 license (no other versions).
 * See the COPYING file included in the main directory of this source
 * distribution for the license terms and conditions.
 *
 * @file    ctdrv.h
 *
 * @breaf
 * This file contains the definition of the programming interfaces that
 * provided by the driver module.
 *
 * @author Liu Chun
 *
 */
 
#ifndef CTDRV_H
#define CTDRV_H
 
#define PCI_VENDOR_CREATIVE             0x1102
#define PCI_DEVICE_CREATIVE_20K1        0x0005
#define PCI_DEVICE_CREATIVE_20K2        0x000B
#define PCI_SUBVENDOR_CREATIVE          0x1102
#define PCI_SUBSYS_CREATIVE_SB0760      0x0024
#define PCI_SUBSYS_CREATIVE_SB0880      0x0041
#define PCI_SUBSYS_CREATIVE_HENDRIX     0x6000
 
#define CT_XFI_DMA_MASK                 0xffffffffUL /* 32 bits */
 
#endif /* CTDRV_H */
 

Now change the definition of PCI_SUBSYS_CREATIVE_SB0880 to the value you have detected before

#define PCI_SUBSYS_CREATIVE_SB0880      0x0042

and build the driver as described in the README document.

Update 2009-05-19: Finally ALSA support has arrived!