Resizeable BAR BIOS issues in Ubuntu

I just updated my GPU BIOS to enable resizeable BAR on Windows for gaming etc (which works fine), but now when I try to boot into Linux, I’m just met with a flashing underscore. I flicked the BIOS switch to the secondary on my GPU (luckily it has one) and it boots in correctly now, which leads me to believe its the updated VBIOS causing the issue. Is there a compatible Linux driver yet? I don’t want to go through the hassle of uninstalling and reinstalling things if its not going to work anyway.

Ubuntu 20.04
Driver Version 455.32.00 (Cuda 11.1)
RTX 3090 Aorus Master


I don’t think it’s supported by the driver (yet). 455 for sure is too old. But I can’t remember reading anything about ReBar support in any of the 460 series release notes. Also a quick search didn’t turn up anything different. The kernel supports it, but I guess we’ll have to wait for the driver.

I thought that would be the case, I understand that the driver version numbers between Windows and Linux are probably not entirely coupled but seeing that I had 465.89 on Windows and the latest for Linux is 460.67 I presume its reasonably behind.

Well, as I couldn’t be bothered opening my case to switch the VBIOS switch every time I want to use the other OS, I guess I’ll continue without ReBar on Windows, it negligible gains most of the time anyway lol.

460.56 supports the RTX3060 which has the rbar feature ootb. Also, please make sure you installed the OS in EFI mode, not using the CSM. Did you have the “above 4G decoding” or similar enabled in bios before flashing the vbios?

Do you have any link that would provide the information, that ReBar support is in the driver?
OP has an RTX3090 (of which he updated the VBIOS), and yes I know the RTX3060 has it built in.
But I’m unable to find any information about that feature being included in the linux driver.

Yeah its all done correctly (BIOS options and all according to the update guide provided by Gigabyte/Aorus), as I said it works fine in Windows and Nvidia Control Panel confirms its on and working.
I’ve previously cooked the process when deleting and reinstalling Drivers/CUDA Toolkit etc when moving from 1070Ti → 3090, which is likely me just being just being braindead at the time, but I don’t want to go through that effort if its not going to work anyway.
The last driver doesn’t explicitly mention ReBar so I’m not sure about it actually implemented in that driver or not. If someone actually has it working on their system, I’d be confident to upgrade then, otherwise I’ll just vibe with the old BIOS until its done. Although TRT still isn’t on 20.04 so I’m not on the edge of my seat for an update anytime soon haha.

While resizable bar support is not explicitly mentioned for the linux driver, this shouldn’t matter for basic functionality. With rbar vbios, the geforce should behave similar to a tesla, i.e. requesting a large bar1 to map a large part of the vmem into cpu address ranges. So the same system bios quirks regarding 64bit bar support and csm apply regardless of any driver loaded.
Whether or not the driver then gets along with the vbios and rbar is actually used, is secondary imho.
Please run as root and attach the resulting nvidia-bug-report.log.gz file to your post.