Months later when this binary X-Fi driver was supposed to be released, Creative Labs mentioned that Vista made them dupe Linux since it took more resources to get the X-Fi driver up and running on Microsoft Windows Vista than they realized and so their Linux development efforts suffered as a result. Later that year they released a Linux X-Fi driver that was not only months late but it only supported 64-bit Linux and had other issues too. Their first Linux driver release was in September of 2007 and then in April 2008 they released another Linux driver. This driver did contain 32-bit support, but wasn't close to being bug free.
Though in February of 2008, a rudimentary open-source driver for the Creative X-Fi had appeared in the Open Sound System. 4Front Technologies, the company behind OSS, was given header files and specifications from Creative Labs to construct this driver. Two months later we learned that Creative was joining the open-source bandwagon. They supplied information to 4Front Technologies and also promised to supply documentation to an ALSA developer, however, after this announcement there was not much movement in the way of an ALSA driver for the Creative X-Fi.
With the binary X-Fi driver, even a year after its release it still was a horrific mess that would not work properly. Though just weeks after that point an initial ALSA X-Fi driver had appeared, but it was a rather hacked together solution based upon the OSS sbxfi driver -- the developer didn't even have an X-Fi sound card to test the driver. In November though Creative open-sourced their X-Fi driver after realizing defeat. While Creative's source-code was freely available, they continued to shaft Linux users by not communicating with ALSA developers that had been attempting to communicate with them regarding technical information for the X-Fi APUs.
While this has been a long and dirty mess, the good news is that as of today there is a merge-able version of the Creative X-Fi driver for ALSA. Novell's Takashi Iwai who wrote the original X-Fi driver has managed to get in contact with Creative Labs to create this genuine X-Fi ALSA driver, which is in far better condition than his previous hack-ish attempt. This new Sound Blaster X-Fi driver is called snd-ctxfi and more information on it can be found within the ALSA development list.
Takashi will be merging this into the mainline ALSA code-base soon so that it will appear in the next Linux kernel, which will be Linux 2.6.31. Finally there is an ALSA driver to provide support for the Creative Labs Sound Blaster X-Fi sound cards, which should begin appearing in desktop Linux distributions this fall.