0007845: Intel X540-AT2 NICs don't advertise "100baseT/Full" when supported on kernel 2.6.32-504.el6

After upgrading the CentOS kernel to 2.6.32-504.el6, provided in standard with CentOS 6.6, the Intel X540-AT2 NIC (using the driver ixgbe) doesn't advertise the link mode "100baseT/Full" (Fast Ethernet) although it is supported by the NIC. It only advertises "1000baseT/Full" (Gigabit Ethernet) and "10000baseT/Full" (10-Gigabit Ethernet).<br /> This causes losses of connectivity when connected to Fast Ethernet (100baseT) network ports (read switches).<br /> <br /> The issue is not present when booted using the previous kernel versions, such as 2.6.32-431.29.2. It is also possible to bypass the issue by manually setting the advertised network link speeds.