I am reasonably experienced with linux, I was a systems admin for more years than I can remember before I retired. I have come across something on my system that is more of a nuisance than a real problem, but I'd like to fix it if I can, and was wondering if somebody here could offer some help.

In need of more storage space and with no free SATA ports, I opted to investigate the addition of these new (to me) NVME drives sat directly on the PCI-X bus. I got them working eventually and they are now set up and working well enough in a RAID 1 configuration. Yes, I don't get the advertised data transfer speeds (probably because of my rather elderly hardware), but it's adequate for me and meets my needs.

I mainly run Fedora, but can dual boot into Linux Mint if needed, this issue occurs on both OS's.

On some, but not every boot my display becomes very "choppy" for want of a better way of describing it, it freezes for a few seconds, then releases only to freeze again a few seconds later. It really makes the computer unusable. A reboot seems to fix this issue, simply a nuisance really, but it got me thinking, and that's where I become stuck.

I really don't know enough about what is happening on the PCI-X bus, all sort of interrupts and lanes and things that really I've never had to worry to much about in the past. Obviously I know what they are, just never had to learn about.

My current thinking is that my Nvidia graphics card is also sat on the same bus as the NVME cards. I know linux can be arbitrary in handing out device names at boot sometimes, and I'm wondering if it's the same with IRQ's, is this "choppy" display an IRQ conflict issue between the graphics card and NVME cards? A reboot "renumbers" the IRQ's then all appears fine?

So I have several questions.

1) How would I go about investigating if this is an issue?
2) Should it be an IRQ issue, is there a way of setting these IRQ's to a set value.

Any help or advice would be hugely appreciated. I don't think it's a "bug" in the system that could be reported to someone, rather it's a config issue in an area I don't fully understand.

Thanks.

I would rather check log files, not irq and pci.

I would expect IRQ conflicts to show up somehow in dmesg.

Sometimes IRQ problems can be solved via a BIOS upgrade.

What motherboard model is this? What CPU?

What model NVidia? NVidia's own drivers, or FOSS graphics drivers?

Thank you for your response. I too would have thought that conflicts (if that's what it is) would show up in a log or dmesg. But to be frank, I can't say I know what I'd be looking for. My hardware is:

M/B Asus M5A99FX PRO R2.0
CPU AMD FX-9370 Eight-Core Processor
GPU GeForce GTX 770

I am currently using the Nvidia driver provided by RPMFusion which I understand to be a repackaged item direct from Nvidia. I have previously used the driver provided by Nvidia, but found it a pain the a**e to install and get working, particularly under Fedora. I only use Fedora, because when I was working, most of my training and experience was on Red Hat. As previously mentioned I can dual boot into Linux Mint, but I get the same issue there also.

With a few tweaks here and there, I've had this hardware setup for nearly 10 years without any real problems. It's only since the addition of the NVME drives that the problem began. If as you suggest it might be a BIOS problem. I flashed the BIOS to the latest (according to Asus) years ago, so there's nowhere to go on that.

Due to the age of your host AM3+ socket (and CPU families it supports), and of NVME, both released the same summer of 13 years ago, I wonder if you'd have better luck if you could use a PCIe NVME host instead of PCI-X.