Issue with Radeon 550x passthrough

I have two GPUs. I try passthrough radeon 550x.
I have problem on last step. I start HVM qube with added pci, but lspci -k inside appVM I have this:

00:07.0 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] Lexa [Radeon 540X/550X/630 / RX 640 / E9171 MCM] (rev c0)
	Subsystem: Acer Incorporated [ALI] Lexa [Radeon 540X/550X/630 / RX 640 / E9171 MCM]
	Kernel modules: amdgpu

So I have not Kernel driver in use: amdgpu amd amdgpu driver not work.

I tryed different distros. When I use example Debian or linux mint on this laptop all drivers work OK and GPU work good too, so it is not problem of packages inside the appVM. But inside qube with passthroughed GPU on the same distro amdgpu driver does not work. I really do not know why.

I use rd.qubesos.hide_pci=01:00.0 in grub config, so I have this in lspci -k inside dom0:

01:00.0 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] Lexa [Radeon 540X/550X/630 / RX 640 / E9171 MCM] (rev c0)
	Subsystem: Acer Incorporated [ALI] Device 152b
	Kernel driver in use: pciback
	Kernel modules: amdgpu

This is lspci -k inside appVM: ZeroBin
This is lspci -k inside dom0: ZeroBin

I Try to passthrough this pci device:

01:00.0 Display controller: Advanced Micro Devices, Inc. [AMD/ATI] Lexa [Radeon 540X/550X/630 / RX 640 / E9171 MCM] (rev c0)

And I know qubesos has problem when use more then 3.5 GB RAM for qube with gpu passthrough. And I have this problem too. May be it can help for understand where problem.

Thanks for any help.
Have you any ideas?