Display resolution limited to 2560x1600

I’m connecting to a virtual workstation using Nice DCV, and I’m unable to use resolutions higher than 2560x1600. What causes this limitation? Here’s the error in Xorg log file.

[ 11558.675] (--) NVIDIA(GPU-0): NVIDIA VGX (DFP-0): connected
[ 11558.675] (--) NVIDIA(GPU-0): NVIDIA VGX (DFP-0): External TMDS
[ 11558.675] (WW) NVIDIA(GPU-0): Mode (3840 x 2400) larger than per-head max resolution
[ 11558.675] (WW) NVIDIA(GPU-0):     supported (2560 x 1600)

I read that some vGPU licenses are limited to 2560x1600. But according to nvidia-smi this is not a vGPU.

# nvidia-smi vgpu
No supported devices in vGPU mode
# nvidia-smi -q

==============NVSMI LOG==============

Timestamp                                 : Thu Jun 15 02:38:57 2023
Driver Version                            : 525.89.02
CUDA Version                              : 12.0

Attached GPUs                             : 1
GPU 00000000:00:1E.0
    Product Name                          : Tesla T4
    Product Brand                         : NVIDIA
    Product Architecture                  : Turing
    Display Mode                          : Enabled
    Display Active                        : Disabled
    Persistence Mode                      : Disabled
    MIG Mode
        Current                           : N/A
        Pending                           : N/A
    Accounting Mode                       : Disabled
    Accounting Mode Buffer Size           : 4000
    Driver Model
        Current                           : N/A
        Pending                           : N/A
    Serial Number                         : 1325121103675
    GPU UUID                              : GPU-f292bdfc-c478-a47e-4196-af022ca72721
    Minor Number                          : 0
    VBIOS Version                         : 90.04.96.00.02
    MultiGPU Board                        : No
    Board ID                              : 0x1e
    Board Part Number                     : 900-2G183-A800-001
    GPU Part Number                       : 1EB8-895-A1
    Module ID                             : 1
    Inforom Version
        Image Version                     : G183.0200.00.02
        OEM Object                        : 1.1
        ECC Object                        : 5.0
        Power Management Object           : N/A
    GPU Operation Mode
        Current                           : N/A
        Pending                           : N/A
    GSP Firmware Version                  : 525.89.02
    GPU Virtualization Mode
        Virtualization Mode               : Pass-Through
        Host VGPU Mode                    : N/A
    IBMNPU
        Relaxed Ordering Mode             : N/A
    PCI
        Bus                               : 0x00
        Device                            : 0x1E
        Domain                            : 0x0000
        Device Id                         : 0x1EB810DE
        Bus Id                            : 00000000:00:1E.0
        Sub System Id                     : 0x12A210DE
        GPU Link Info
            PCIe Generation
                Max                       : 3
                Current                   : 3
                Device Current            : 3
                Device Max                : 3
                Host Max                  : N/A
            Link Width
                Max                       : 16x
                Current                   : 8x
        Bridge Chip
            Type                          : N/A
            Firmware                      : N/A
        Replays Since Reset               : 0
        Replay Number Rollovers           : 0
        Tx Throughput                     : 0 KB/s
        Rx Throughput                     : 0 KB/s
        Atomic Caps Inbound               : N/A
        Atomic Caps Outbound              : N/A
    Fan Speed                             : N/A
    Performance State                     : P0
    Clocks Throttle Reasons
        Idle                              : Not Active
        Applications Clocks Setting       : Not Active
        SW Power Cap                      : Not Active
        HW Slowdown                       : Not Active
            HW Thermal Slowdown           : Not Active
            HW Power Brake Slowdown       : Not Active
        Sync Boost                        : Not Active
        SW Thermal Slowdown               : Not Active
        Display Clock Setting             : Not Active
    FB Memory Usage
        Total                             : 15360 MiB
        Reserved                          : 399 MiB
        Used                              : 782 MiB
        Free                              : 14178 MiB
    BAR1 Memory Usage
        Total                             : 256 MiB
        Used                              : 11 MiB
        Free                              : 245 MiB
    Compute Mode                          : Default
    Utilization
        Gpu                               : 0 %
        Memory                            : 0 %
        Encoder                           : 0 %
        Decoder                           : 0 %
    Encoder Stats
        Active Sessions                   : 0
        Average FPS                       : 0
        Average Latency                   : 0
    FBC Stats
        Active Sessions                   : 0
        Average FPS                       : 0
        Average Latency                   : 0
    Ecc Mode
        Current                           : Enabled
        Pending                           : Enabled
    ECC Errors
        Volatile
            SRAM Correctable              : 0
            SRAM Uncorrectable            : 0
            DRAM Correctable              : 0
            DRAM Uncorrectable            : 0
        Aggregate
            SRAM Correctable              : 0
            SRAM Uncorrectable            : 0
            DRAM Correctable              : 0
            DRAM Uncorrectable            : 0
    Retired Pages
        Single Bit ECC                    : 0
        Double Bit ECC                    : 0
        Pending Page Blacklist            : No
    Remapped Rows                         : N/A
    Temperature
        GPU Current Temp                  : 39 C
        GPU T.Limit Temp                  : N/A
        GPU Shutdown Temp                 : 96 C
        GPU Slowdown Temp                 : 93 C
        GPU Max Operating Temp            : 85 C
        GPU Target Temperature            : N/A
        Memory Current Temp               : N/A
        Memory Max Operating Temp         : N/A
    Power Readings
        Power Management                  : Supported
        Power Draw                        : 24.98 W
        Power Limit                       : 70.00 W
        Default Power Limit               : 70.00 W
        Enforced Power Limit              : 70.00 W
        Min Power Limit                   : 60.00 W
        Max Power Limit                   : 70.00 W
    Clocks
        Graphics                          : 585 MHz
        SM                                : 585 MHz
        Memory                            : 5000 MHz
        Video                             : 810 MHz
    Applications Clocks
        Graphics                          : 585 MHz
        Memory                            : 5001 MHz
    Default Applications Clocks
        Graphics                          : 585 MHz
        Memory                            : 5001 MHz
    Deferred Clocks
        Memory                            : N/A
    Max Clocks
        Graphics                          : 1590 MHz
        SM                                : 1590 MHz
        Memory                            : 5001 MHz
        Video                             : 1470 MHz
    Max Customer Boost Clocks
        Graphics                          : 1590 MHz
    Clock Policy
        Auto Boost                        : N/A
        Auto Boost Default                : N/A
    Voltage
        Graphics                          : N/A
    Fabric
        State                             : N/A
        Status                            : N/A
    Processes
        GPU instance ID                   : N/A
        Compute instance ID               : N/A
        Process ID                        : 92301
            Type                          : G
            Name                          : /usr/libexec/Xorg
            Used GPU Memory               : 92 MiB
        GPU instance ID                   : N/A
        Compute instance ID               : N/A
        Process ID                        : 92387
            Type                          : G
            Name                          : /usr/bin/gnome-shell
            Used GPU Memory               : 68 MiB
        GPU instance ID                   : N/A
        Compute instance ID               : N/A
        Process ID                        : 93962
            Type                          : C+G
            Name                          : /usr/libexec/dcv/dcvagent
            Used GPU Memory               : 535 MiB

OS: Rocky Linux 8.7
Platform: AWS EC2 g4dn.8xlarge
GPU: Tesla T4
Driver: 525.89.02
Xorg.0.log (24.3 KB)

While you’re not using vGPU software, Teslas still use virtual heads with that limitation when used as graphics device. IIRC, on older Teslas it was possible to fake a “real” head using the ConnectedMonitor xorg.conf option but I don’t know if that still works.