I used the LSI 9240-8i card on a smaller Intel motherboard with no problems in Ubuntu, with ZFS.

However, we rebuilt the server to allow for more disks, using the ASROCK X79 Extreme 11 motherboard. It has 7 PCIe slots, and a LSI 2008 on-board. At first I thought the LSI 9240, when plugged in to PCIe, clashed with the on-board LSI 2008. Every time I plugged in the LSI 9240, modprobe would hang. Then I completely disabled the on-board LSI 2008, and the problem persisted.

Last night it booted perfectly ONCE - all LSI cards and connected disks visible... However, all subsequent reboots failed. Both LSI cards' bios scans appear and they both see the disks connected to them, but Ubuntu modprobe hangs.

Some selected dmesg lines, with both LSI cards enabled:

[  190.752100] megasas: [ 0]waiting for 1 commands to complete
[  195.772071] megasas: [ 5]waiting for 1 commands to complete
[  200.792079] megasas: [10]waiting for 1 commands to complete
[  205.812078] megasas: [15]waiting for 1 commands to complete
[  210.832037] megasas: [20]waiting for 1 commands to complete
[  215.852077] megasas: [25]waiting for 1 commands to complete
[  220.872072] megasas: [30]waiting for 1 commands to complete
[  225.892078] megasas: [35]waiting for 1 commands to complete
[  230.912086] megasas: [40]waiting for 1 commands to complete
[  235.932075] megasas: [45]waiting for 1 commands to complete
[  240.306157] usb 2-1.5: USB disconnect, device number 7
[  240.952076] megasas: [50]waiting for 1 commands to complete
[  240.960034] INFO: task modprobe:233 blocked for more than 120 seconds.
[  240.960055] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[  240.960067] modprobe        D ffffffff81806200     0   233    146 0x00000004
[  240.960075]  ffff880806ae3b48 0000000000000086 ffff880806ae3ae8 ffffffff8101adf3
[  240.960083]  ffff880806ae3fd8 ffff880806ae3fd8 ffff880806ae3fd8 0000000000013780
[  240.960090]  ffffffff81c0d020 ffff880806acae00 ffff880806ae3b58 ffff880808961720
[  240.960096] Call Trace:
[  240.960107]  [<ffffffff8101adf3>] ? native_sched_clock+0x13/0x80
[  240.960116]  [<ffffffff816579cf>] schedule+0x3f/0x60
[  240.960137]  [<ffffffffa00093f5>] megasas_issue_blocked_cmd+0x75/0xb0 [megaraid_sas]
[  240.960144]  [<ffffffff8108aa50>] ? add_wait_queue+0x60/0x60
[  240.960154]  [<ffffffffa000a6c9>] megasas_get_seq_num+0xd9/0x260 [megaraid_sas]
[  240.960164]  [<ffffffffa000ab31>] megasas_start_aen+0x31/0x60 [megaraid_sas]
[  240.960174]  [<ffffffffa00136f1>] megasas_probe_one+0x69a/0x81c [megaraid_sas]
[  240.960182]  [<ffffffff813345bc>] local_pci_probe+0x5c/0xd0
[  240.960189]  [<ffffffff81335e89>] __pci_device_probe+0xf9/0x100
[  240.960197]  [<ffffffff8130ce6a>] ? kobject_get+0x1a/0x30
[  240.960205]  [<ffffffff81335eca>] pci_device_probe+0x3a/0x60
[  240.960212]  [<ffffffff813f5278>] really_probe+0x68/0x190
[  240.960217]  [<ffffffff813f5505>] driver_probe_device+0x45/0x70
[  240.960223]  [<ffffffff813f55db>] __driver_attach+0xab/0xb0
[  240.960227]  [<ffffffff813f5530>] ? driver_probe_device+0x70/0x70
[  240.960233]  [<ffffffff813f5530>] ? driver_probe_device+0x70/0x70
[  240.960237]  [<ffffffff813f436c>] bus_for_each_dev+0x5c/0x90
[  240.960243]  [<ffffffff813f503e>] driver_attach+0x1e/0x20
[  240.960248]  [<ffffffff813f4c90>] bus_add_driver+0x1a0/0x270
[  240.960255]  [<ffffffffa001e000>] ? 0xffffffffa001dfff
[  240.960260]  [<ffffffff813f5b46>] driver_register+0x76/0x140
[  240.960266]  [<ffffffffa001e000>] ? 0xffffffffa001dfff
[  240.960271]  [<ffffffff81335b66>] __pci_register_driver+0x56/0xd0
[  240.960277]  [<ffffffffa001e000>] ? 0xffffffffa001dfff
[  240.960286]  [<ffffffffa001e09e>] megasas_init+0x9e/0x1000 [megaraid_sas]
[  240.960294]  [<ffffffff81002040>] do_one_initcall+0x40/0x180
[  240.960301]  [<ffffffff810a82fe>] sys_init_module+0xbe/0x230
[  240.960307]  [<ffffffff81661ec2>] system_call_fastpath+0x16/0x1b
[  240.960314] INFO: task scsi_scan_7:349 blocked for more than 120 seconds.