Update: I very much doubt that anyone should be using this anymore. The discard mount option has been working properly for years. In fact, you probably should use hdparm to manually TRIM your drive. You should be using fstrim. It is available in the software repositories of most recent Linux distributions.

The wiper.sh script that ships with hdparm 9.27 does not work well with the Intel X25 drives. The call to hdparm will fail if it is passed in more than 512 ranges of sectors. I made a quick and dirty modification to the wiper.sh script so that it makes multiple calls to hdparm with 500 ranges each. I've only been running it for a few days, but it seems to be working just fine so far.

I also added a --yes command line switch so that I could more easily call it from cron.

wonko@zaphod:~$ sudo ./wiper-dangerous.sh --commit --yes /

wiper-dangerous.sh: Linux SATA SSD TRIM utility, version 2.5-dangerous, by Mark Lord.
Preparing for online TRIM of free space on /dev/sda2 (ext4 mounted read-write at /).
Creating temporary file (3091782 KB).. 
Syncing disks.. 
Beginning TRIM operations..

/dev/sda:
trimming 6183568 sectors from 159 ranges
succeeded
Removing temporary file..
Syncing disks.. 
Done.

The script also now has a dependency on Perl. Feel free to download a copy of my wiper-dangerous.sh, but I make no promise that it won't eat your data!