QLogic Fibre Channel HBA does not work, reporting "Cable is unplugged..."

Issue

• The QLogic HBA is detected correctly, but the available LUN are not visible on the server.

• /var/log/messages lists the following:

qla2300 0000:05:07.0: Found an ISP2312, irq 193, iobase 0xffffc2000001c000
qla2300 0000:05:07.0: Configuring PCI space...
qla2300 0000:05:07.0: Configure NVRAM parameters...
qla2300 0000:05:07.0: Verifying loaded RISC code...
qla2300 0000:05:07.0: Allocated (412 KB) for firmware dump...
qla2300 0000:05:07.0: Waiting for LIP to complete...
qla2300 0000:05:07.0: Cable is unplugged...

qla2xxx [0000:08:00.0]-0005: : QLogic Fibre Channel HBA Driver: 8.06.00.08.07.0-k2
qla2xxx [0000:08:00.0]-011c: : MSI-X vector count: 31.
qla2xxx [0000:08:00.0]-001d: : Found ISP2031 irp 40 iobase 0xFFFFc9001685a000.
qla2xxx 0000:08:00.0: irq 124 for MSI/MSI-X
qla2xxx 0000:08:00.0: irq 125 for MSI/MSI-X
qla2xxx [0000:08:00.0]-0075:0: ZIO mode 6 enabled; timer delay (200us).
scsi0 : qla2xxx
qla2xxx [0000:08:00.0]-00fb:0: QLogic QMH2627 - HP QMH2672 16Gb 2P FC HBA.
qla2xxx [0000:08:00.0]-00fc:0: ISP2031: PCIe (8.0GT./s x8) @ 0000:08:00.0 hdma+ host#=0 fw=7.04.00 (d0d5).
qla2xxx [0000:08:00.0]-08038:0: Cable is unplugged...

• Even though the cable is connected, the HBA firmware does not detect it:

qla2300 0000:05:07.0: Cable is unplugged...

• Attempting to mounting ext4 file systems hangs with following call traces

INFO: task mount:30132 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
mount         D 0000000000000013     0 30132  29728 0x00000080
 ffff8839c7591b18 0000000000000082 ffff8839c7591ad8 ffffffffa00043ec
 ffff88404fece200 0000000000000002 0000000000000024 000000000fd00011
 ffff88404396c638 ffff8839c7591fd8 000000000000fb88 ffff88404396c638
Call Trace:
 [<ffffffffa00043ec>] ? dm_table_unplug_all+0x5c/0x100 [dm_mod]
 [<ffffffff810a1ac9>] ? ktime_get_ts+0xa9/0xe0
 [<ffffffff811b6040>] ? sync_buffer+0x0/0x50
 [<ffffffff8150df53>] io_schedule+0x73/0xc0
 [<ffffffff811b6080>] sync_buffer+0x40/0x50
 [<ffffffff8150e90f>] __wait_on_bit+0x5f/0x90
 [<ffffffff811b6040>] ? sync_buffer+0x0/0x50
 [<ffffffff8150e9b8>] out_of_line_wait_on_bit+0x78/0x90
 [<ffffffff81096ce0>] ? wake_bit_function+0x0/0x50
 [<ffffffff811b6036>] __wait_on_buffer+0x26/0x30
 [<ffffffff811b71c6>] __bread+0x76/0xb0
 [<ffffffffa0154685>] ext4_fill_super+0x1d5/0x27e0 [ext4]
 [<ffffffff8150e3cd>] ? wait_for_completion+0x1d/0x20
 [<ffffffff81092b58>] ? synchronize_sched+0x58/0x60
 [<ffffffff811844ae>] get_sb_bdev+0x18e/0x1d0
 [<ffffffffa01544b0>] ? ext4_fill_super+0x0/0x27e0 [ext4]
 [<ffffffffa014f648>] ext4_get_sb+0x18/0x20 [ext4]
 [<ffffffff811838fb>] vfs_kern_mount+0x7b/0x1b0
 [<ffffffff81183aa2>] do_kern_mount+0x52/0x130
 [<ffffffff811a3cf2>] do_mount+0x2d2/0x8d0
 [<ffffffff81139f34>] ? strndup_user+0x64/0xc0
 [<ffffffff811a4380>] sys_mount+0x90/0xe0
 [<ffffffff8100b072>] system_call_fastpath+0x16/0x1b