Odd issue... Install Pop_OS, on reboot, system can't post to gtx970

So I’m starting on some vfio stuff, hoping to get that running today, and got pop installed. Using a gigabyte x470 Aorus Ultra Gaming. It saw no problem with my GTX970 and RX480 both being in my system, so I blacklisted the 480 as thats what will be used to pass through, got some stuff setup, and had to reboot.

Well, now my system is sitting pre-post, does make a post beep, but doesn’t display to the 970. Remove the 480, posts fine. After a couple bops on the reset switch I got it to boot correctly once.

The gtx970 is in slot one, the rx480 is in slot 2. I’m a little baffled. It booted to windows multiple times with both cards in just fine.

Ideas?

I have already tried a cmos clear.

May just be a display adapter issue with the Nvidia card, the classic “no modeset” problem. It basically gets confused as to display resolutions.

I was surprised to see it still happening on a recent install of Manjaro on an old gtx 1050.

Try booting with no monitor plugged in until you are sure the boot sequence is done, then plug in the monitor. That usually worked for me. You can then set up the display correctly and save settings, and it won’t do it again.

If not this then it may be an iommu issue but try this first.

Well, its not even getting to post screen is the thing. My BIOS puts a little _ in the top corner before the gigabyte logo, and that displays just fine.

I just reboot, pulled the 480, and fucked around in bios. Set IOMMU to enable, I think it was set to auto before. I think its working now but I’ll be investigating this further.

Nope did it again.

This is so stupid

I think it just doesn’t know what ta boot from so it just halts. Pop_OS didn’t install grub, so I plugged a usb in, bang, sure enough it boots right up into windows.

Are you fucking kidding me

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I see. Thinking out loud… Your second GPU would have split your pcie lanes. Removing one would then reallocate lanes. Linux expects your (presume nvme) SSD to be at a certain address. Changing the config changes the address of the SSD.

Can you enter bios and change the boot drive to force it?

No I couldn’t do anything. Its ok now tho ty

System76 IRC Channels would also be a good place to ask for help and open a ticket with them.

IRC Channels on Freenode. This is System76’s channel description with link to support tickets: Welcome to the Official System76 Channel! | System76 Staff are voiced in this channel. | https://system76.com | Have a support issue? Open a support case at http://s76.co/accnt | Pop!_OS 19.04 ISOs are here! https://system76.com/pop

IRC Channels are really great places to get support, help other and also learn along the way. Guessing it is based upon Ubuntu and not Debian so Ubuntu IRC channels might be worth a try if Pop support doesn’t suffice.