proxmox 1070ti passthrough result in black screen

[k1lerbee]

I am running proxmox 6.1.2 on

• ryzen 2600
• Asus TUF B450m gaming plus
• 16 gb ddr4 3000mhz ram
• Asus Cerberus GTX 1070 TI 8GB(primary slot)
• Palit gt 710 1GB (secondary slot)

I have mainly followed this guide to passthrough my 1070ti :
https://pve.proxmox.com/wiki/Pci_passthrough
and also https://www.reddit.com/r/homelab/comments/b5xpua/the_ultimate_beginners_guide_to_gpu_passthrough/
and other guides I could find trying to make my 1070 ti work.
When I start my VM (which has 1070 ti configured on it), I get a black screen on the 1070 ti output... the vm seems to work (cpu and memory usage changes)... using RDP, I see only a cursor with black background.
I am using seabios as it is an existing windows non-uefi install on an ssd.
I have done a test with Palit gt 710 1GB and with the latter, it works fine with no issues.

Here are my configs:
/etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="quiet amd_iommu=on iommu=pt pcie_acs_override=downstream,multifunction nofb nomodeset video=vesafb:off,efifb:off"

/etc/modules

vfio vfio_iommu_type1 vfio_pci vfio_virqfd

/etc/modprobe.d/iommu_unsafe_interrupts.conf

options vfio_iommu_type1 allow_unsafe_interrupts=1

/etc/modprobe.d/vfio.conf

options vfio-pci ids=10de:1b81,10de:10f0

My vm conf

args: -cpu 'host,+kvm_pv_unhalt,+kvm_pv_eoi,hv_vendor_id=NV43FIX,kvm=off'
bootdisk: sata0
cores: 4
cpu: host,hidden=1,flags=+pcid
hostpci0: 06:00,pcie=1,x-vga=1,romfile=asus-cerberus-gtx-1070ti-GP104.rom
machine: q35
memory: 8000
name: win10 net0: e1000=7E:2D:A6:EA:78:8B,bridge=vmbr0,firewall=1
numa: 1
ostype: win10
sata0: /dev/disk/by-id/ata-Samsung_SSD_850_EVO_250GBxxxxL,size=244198584K,ssd=1
scsihw: virtio-scsi-pci
smbios1: uuid=d148623b-9113-47d5-98da-743a54546cd4

Doing dmesg, I get
dmesg | grep vfio

[    6.193394] vfio-pci 0000:06:00.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=io+mem:eek:wns=io+mem
[    6.212043] vfio_pci: add [10de:1b82[ffffffff:ffffffff]] class 0x000000/00000000
[    6.236169] vfio_pci: add [10de:10f0[ffffffff:ffffffff]] class 0x000000/00000000
[   87.680845] vfio-pci 0000:06:00.0: vfio_ecap_init: hiding ecap 0x19@0x900
[   87.683399] vfio-pci 0000:06:00.0: No more image in the PCI ROM

2 things I noticed with the dmesg:

1. the gpu does not seem to start. There is no line like [ 8.935135] vfio-pci 0000:06:00.0: enabling device (0000 -> 0003) as I could see in guides.
2. I get "No more image in the PCI ROM" even if I have configured a romfile in my vm conf. I have dumped my vbios using gpu-z. I also tried dumping as explained in https://pve.proxmox.com/wiki/Pci_passthrough and I also tried a rom from techpowerup

I have tried all sorts of variants on the configurations but still no luck.

p.s. I had the 1070 ti working before on proxmox but I had issues with shutting down the vm and host. So I updated my mobo's bios... after the mobo bios, I don't get the shutting down issues but I don't get any output now.

 

[k1lerbee]

I was able to solve the issue by following this guide for UNRAID .. dumping and hex edit the vbios:
https://www.youtube.com/watch?v=1IP-h9IKof0

But I have some minor issues in the VM... micro stutter when gaming and no gaming (less less frequent) with some weird audio when the stutter occur... need to do some more tests