I have the following devices that is assigned to IRQ15 as the default in the Dell BIOS:

02:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1068E PCI-Express Fusion-MPT SAS (rev 08)
01:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5716 Gigabit Ethernet (rev 20)
00:00.0 Host bridge: Intel Corporation 5500 I/O Hub to ESI Port (rev 13)

I installed a Digium TE420B telephony card into the PCIe slot and Dell assigned it to IRQ15 as well.

I need my Digium card to be on its own IRQ. It simply cannot share IRQ as eventually any slightest interrupt latency which would not be noticeable for other things such as the NIC, USB, video, sound etc which can share IRQs, this card CANNOT. The Digium card is a realtime telephony card and it is very sensitive. We are getting CRC errors traced back to the IRQ sharing running low level timing accuracy test.

What I have done so far to alleviate the issue is by disabling one of the embedded NIC on IRQ15 and using the other NIC on IRQ14. I have disabled all USB ports. So the only thing left is the RAID SAS controller sharing the IRQ. Is there a way to remap the IRQ either thru the bios or a pin on the motherboard I can shift around? Changing in the bios does not allow me to dedicate the PCIe slot to its own IRQ. Any change to the PCIe IRQ changes the other 3 devices with it as well resulting still in a shared IRQ.

I am running Centos 5.2 Kernel 2.6.x and have not found a way to override through the OS but so far everyone suggest I should not try to override in the OS as that will be more problematic especially if this is a hardware path limitation.

Dell Support have not been able to assist and directed me to post here. I need a resolution for this as we have another R410 server with the same hardware setup about to go into production and have more on order. How do I find which server model does not share IRQ for future?