Comment 16 for bug 1883111

Tested on focal server using ubuntu-20.04.1-preinstalled-server-arm64+raspi.img.xz as follows:

  Operating System: Ubuntu 20.04.1 LTS
            Kernel: Linux 5.4.0-1015-raspi
      Architecture: arm64

Tested package versions:
libraspberrypi-bin:arm64 (0~20200520+git2fe4ca3-0ubuntu3~20.04),
libraspberrypi0:arm64 (0~20200520+git2fe4ca3-0ubuntu3~20.04, automatic)

sudo apt install libraspberrypi-bin
rebooted

Tested:

ubuntu@pi4b-ubuntu-focal:~$ vcgencmd commands
commands="vcos, ap_output_control, ap_output_post_processing, vchi_test_init, vchi_test_exit, pm_set_policy, pm_get_status, pm_show_stats, pm_start_logging, pm_stop_logging, version, commands, set_vll_dir, set_backlight, set_logging, get_lcd_info, arbiter, cache_flush, otp_dump, test_result, codec_enabled, get_camera, get_mem, measure_clock, measure_volts, enable_clock, scaling_kernel, scaling_sharpness, get_hvs_asserts, get_throttled, measure_temp, get_config, hdmi_ntsc_freqs, hdmi_adjust_clock, hdmi_status_show, hvs_update_fields, pwm_speedup, force_audio, hdmi_stream_channels, hdmi_channel_map, display_power, read_ring_osc, memtest, dispmanx_list, get_rsts, schmoo, render_bar, disk_notify, inuse_notify, sus_suspend, sus_status, sus_is_enabled, sus_stop_test_thread, egl_platform_switch, mem_validate, mem_oom, mem_reloc_stats, hdmi_cvt, hdmi_timings, readmr, pmicrd, pmicwr, bootloader_version, bootloader_config, file, vctest_memmap, vctest_start, vctest_stop, vctest_set, vctest_get"

ubuntu@pi4b-ubuntu-focal:~$ vcgencmd measure_temp
temp=34.0'C
ubuntu@pi4b-ubuntu-focal:~$ vcgencmd measure_temp pmic
temp=28.8'C
ubuntu@pi4b-ubuntu-focal:~$ vcgencmd bootloader_config
[all]
BOOT_UART=0
WAKE_ON_GPIO=1
POWER_OFF_ON_HALT=0

ubuntu@pi4b-ubuntu-focal:~$ tvservice -s
Error getting current display state
ubuntu@pi4b-ubuntu-focal:~$ sudo tvservice -s
vchi_msg_dequeue -> -1(90)
vchi_msg_dequeue -> -1(90)
state 0x1 [TV is off]

So the vcgencmd interface is working, but tvservice is not.