mjhjmtu

I am using CentOS7 7.5.1804. I have a Intel 82599 based 10gig SFP+ card. When I try my SFP's I get:

failed to load because an unsupported SFP+ or QSFP module type was detected.

I tried everything I found online[1] including adding to the kernel options:

ixgbe.allow_unsupported_sfp=1

I also tried

modprobe ixgbe allow_unsupported_sfp=1

In fact when afterwards if I did modinfo -p ixgbe I got back:

[root@codd-b01 ~]# modprobe ixgbe 
[root@codd-b01 ~]# modinfo -p ixgbe
max_vfs:Maximum number of virtual functions to allocate per physical function - default is zero and maximum value is 63 (uint)
allow_unsupported_sfp:Allow unsupported and untested SFP+ modules on 82599-based adapters (uint)
debug:Debug level (0=none,...,16=all) (int)
[root@codd-b01 ~]#

Below you can see all the steps including showing that Linux wont allow the SFP AFTER I unloaded and reloaded the module.

[root@codd-b01 ~]# dmesg | grep SFP
[ 8.981009] ixgbe 0000:5f:00.0: failed to load because an unsupported SFP+ or QSFP module type was detected.
[ 8.994928] ixgbe 0000:5f:00.1: failed to load because an unsupported SFP+ or QSFP module type was detected.
[root@codd-b01 ~]# modprobe -r ixgbe 
[root@codd-b01 ~]# modprobe ixgbe 
[root@codd-b01 ~]# modinfo -p ixgbe
max_vfs:Maximum number of virtual functions to allocate per physical function - default is zero and maximum value is 63 (uint)
allow_unsupported_sfp:Allow unsupported and untested SFP+ modules on 82599-based adapters (uint)
debug:Debug level (0=none,...,16=all) (int)

[root@codd-b01 ~]# dmesg | grep SFP
[ 8.981009] ixgbe 0000:5f:00.0: failed to load because an unsupported SFP+ or QSFP module type was detected.
[ 8.994928] ixgbe 0000:5f:00.1: failed to load because an unsupported SFP+ or QSFP module type was detected.
[ 6324.524966] ixgbe 0000:5f:00.0: failed to load because an unsupported SFP+ or QSFP module type was detected.
[ 6324.538955] ixgbe 0000:5f:00.1: failed to load because an unsupported SFP+ or QSFP module type was detected.
[root@codd-b01 ~]#

The best I found was [2] but I don't have a RHEL subscription.

[1] For instance https://ahelpme.com/linux/kernel/missing-network-interface-10g-intel-x520-with-error-failed-to-load-because-of-unsupported-sfp/

[2] https://access.redhat.com/solutions/275333

It turns out there was some weird issue with the firmware on one side of the optics (I was using a DAC) cable. If it was switched around it would work.