Comment 3 for bug 1755268

I was teted right now, the problem occurs also on stock kernel.

    # uname -a
    Linux m5c43 4.4.0-116-generic #140-Ubuntu SMP Mon Feb 12 21:23:04 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Seems bug connected only with specific hardware, I'll provide more information about this.
I uses HP Moonshot x710x xartridge:

    # lspci
    00:00.0 Host bridge: Intel Corporation Sky Lake Host Bridge/DRAM Registers (rev 0a)
    00:01.0 PCI bridge: Intel Corporation Sky Lake PCIe Controller (x16) (rev 0a)
    00:02.0 VGA compatible controller: Intel Corporation Device 193a (rev 09)
    00:14.0 USB controller: Intel Corporation Sunrise Point-H USB 3.0 xHCI Controller (rev 31)
    00:16.0 Communication controller: Intel Corporation Sunrise Point-H CSME HECI #1 (rev 31)
    00:17.0 SATA controller: Intel Corporation Sunrise Point-H SATA controller [AHCI mode] (rev 31)
    00:1b.0 PCI bridge: Intel Corporation Sunrise Point-H PCI Root Port #17 (rev f1)
    00:1c.0 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root Port #1 (rev f1)
    00:1c.3 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root Port #4 (rev f1)
    00:1c.4 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root Port #5 (rev f1)
    00:1d.0 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root Port #9 (rev f1)
    00:1d.5 PCI bridge: Intel Corporation Sunrise Point-H PCI Express Root Port #14 (rev f1)
    00:1f.0 ISA bridge: Intel Corporation Sunrise Point-H LPC Controller (rev 31)
    00:1f.2 Memory controller: Intel Corporation Sunrise Point-H PMC (rev 31)
    00:1f.4 SMBus: Intel Corporation Sunrise Point-H SMBus (rev 31)
    01:00.0 System peripheral: Hewlett-Packard Company Integrated Lights-Out Standard Slave Instrumentation & System Support (rev 06)
    01:00.1 VGA compatible controller: Matrox Electronics Systems Ltd. MGA G200EH (rev 01)
    01:00.2 System peripheral: Hewlett-Packard Company Integrated Lights-Out Standard Management Processor Support and Messaging (rev 06)
    01:00.4 USB controller: Hewlett-Packard Company Integrated Lights-Out Standard Virtual USB Controller (rev 03)
    0e:00.0 Non-Volatile memory controller: Intel Corporation Device f1a5 (rev 03)
    11:00.0 Ethernet controller: Mellanox Technologies MT27520 Family [ConnectX-3 Pro]
    11:00.1 Ethernet controller: Mellanox Technologies MT27500/MT27520 Family [ConnectX-3/ConnectX-3 Pro Virtual Function]

    # ethtool -i eno1
    driver: mlx4_en
    version: 4.3-1.0.1
    firmware-version: 2.40.5540
    expansion-rom-version:
    bus-info: 0000:11:00.0
    supports-statistics: yes
    supports-test: yes
    supports-eeprom-access: no
    supports-register-dump: no
    supports-priv-flags: yes

    # mst status
    MST modules:
    ------------
        MST PCI module loaded
        MST PCI configuration module loaded

    MST devices:
    ------------
    /dev/mst/mt4103_pci_cr0 - PCI direct access.
                                       domain:bus:dev.fn=0000:11:00.0 bar=0x7f100000 size=0x100000
                                       Chip revision is: 00
    /dev/mst/mt4103_pciconf0 - PCI configuration cycles access.
                                       domain:bus:dev.fn=0000:11:00.0 addr.reg=88 data.reg=92
                                       Chip revision is: 00

    # ibv_devinfo
    hca_id: mlx4_1
            transport: InfiniBand (0)
            fw_ver: 2.40.5540
            node_guid: 0014:0500:d300:bc52
            sys_image_guid: f403:4303:00fd:102d
            vendor_id: 0x02c9
            vendor_part_id: 4100
            hw_ver: 0x0
            board_id: HP_1690110017
            phys_port_cnt: 2
            Device ports:
                    port: 1
                            state: PORT_DOWN (1)
                            max_mtu: 4096 (5)
                            active_mtu: 1024 (3)
                            sm_lid: 0
                            port_lid: 0
                            port_lmc: 0x00
                            link_layer: Ethernet

                    port: 2
                            state: PORT_DOWN (1)
                            max_mtu: 4096 (5)
                            active_mtu: 1024 (3)
                            sm_lid: 0
                            port_lid: 0
                            port_lmc: 0x00
                            link_layer: Ethernet

    hca_id: mlx4_0
            transport: InfiniBand (0)
            fw_ver: 2.40.5540
            node_guid: f403:4303:00fd:102d
            sys_image_guid: f403:4303:00fd:102d
            vendor_id: 0x02c9
            vendor_part_id: 4103
            hw_ver: 0x0
            board_id: HP_1690110017
            phys_port_cnt: 2
            Device ports:
                    port: 1
                            state: PORT_ACTIVE (4)
                            max_mtu: 4096 (5)
                            active_mtu: 1024 (3)
                            sm_lid: 0
                            port_lid: 0
                            port_lmc: 0x00
                            link_layer: Ethernet

                    port: 2
                            state: PORT_ACTIVE (4)
                            max_mtu: 4096 (5)
                            active_mtu: 1024 (3)
                            sm_lid: 0
                            port_lid: 0
                            port_lmc: 0x00
                            link_layer: Ethernet