Comment 13 for bug 1941854

On drift3-amd, the memory is 32G. And in BIOS, there are "UMA frame buffer size", by default it set to 'Auto', and there are also 1GB,2GB,4GB and 8G options. When I set 1G or 2G this testcase is passed, the 'Auto' mean 4G from dmesg. This issue looks not related to Prefetchable value in lspci. It will keep 256M whatever the VRAM's value is.

In this case 4G used as default for shared memory, it sounds good, how could we avoid the failure of memory/info testcase?

Results:
        /proc/meminfo reports: 27.25GiB
        lshw reports: 32GiB

FAIL: Meminfo reports 5104971776 less than lshw, a difference of 14.86%. Only a variance of 10% in reported memory is allowed.

Mar 16 04:49:05 Drift3-AMD-6 kernel: [drm] amdgpu: 4096M of VRAM memory ready
Mar 16 04:49:05 Drift3-AMD-6 kernel: [drm] amdgpu: 4096M of GTT memory ready.

$ sudo lspci -nv | grep Prefetchable
        Prefetchable memory behind bridge: [disabled]
        Prefetchable memory behind bridge: [disabled]
        Prefetchable memory behind bridge: 0000000830000000-00000008301fffff [size=2M]
        Prefetchable memory behind bridge: [disabled]
        Prefetchable memory behind bridge: [disabled]
        Prefetchable memory behind bridge: [disabled]
        Prefetchable memory behind bridge: [disabled]
        Prefetchable memory behind bridge: 0000000860000000-00000008701fffff [size=258M]