LinuxQuestions.org - TRIM/discard not working any more for ext4 partition on SSD

Hi everybody,

recently I noticed that neither

Code:

cat /proc/mounts

nor

Code:

mount

show the discard flag for my ext4 partitions anymore.

The discard option is present in fstab.

Code:

mount -oremount,discard /dev/sda1

and

Code:

tune2fs -o discard /dev/sda1

don't change anything.

Code:

dmesg |grep discard

shows this:
EXT4-fs (sda1): re-mounted. Opts: errors=remount-ro,data=writeback,nobarrier,nobh,discard

So, dmesg indicates that the filesystem was mounted with discard enabled
(but again /proc/mounts does not).

Remember everything was OK until yesterday or so.
Already tried different kernel versions to no avail.

Also, when I boot another distro everything shows up correct.

Any ideas?

Im running Debian sid, amd64.
SSD is a Crucial M4 128 GB, newest F/W (009).