Commtech's Fastcom Product Support Blog

It has come to my attention that some (maybe not all) Linux kernels of the vintage 2.6.27 (specifically Ubuntu 8.10) and later will cause the SuperFastcom driver to seg fault upon being loaded with an insmod.  Apparently someone decided that the DSCC4 kernel module is associated with the PEB20534 serial controller’s PCI device ID and therefore would be the correct driver to load when that PCI device ID is detected.  This would be incorrect.

To get around this problem, you will need to add the DSCC4 and hdlc modules to modprobe’s blacklist so that they do not automatically get loaded.  Edit the file /etc/modprobe.d/blacklist and add these two lines to it somewhere:

blacklist dscc4

blacklist hdlc

Reboot your PC and verify that these two modules are no longer with an lsmod.  You will now be able to correctly insmod the SuperFastcom’s superfc.ko kernel module and use the card as intended.

If anyone knows how to get them to NOT load these modules by default, let me know and I’ll see what I can do.