X-server configuration, Nouveau video driver
    : see https://nouveau.freedesktop.org/
    : see https://wiki.gentoo.org/wiki/Nouveau
    : contra https://lwn.net/Articles/910343/ : 2022, Uncertain prospects for Nouveau.

    ! Windows misdrawn on rotated screens that use a hardware cursor.
        : see 40_video_ports.conf : note [HWC]
        - My workaround is to disable the hardware cursor.
    ! Very slow.
        / Revealed by dragging my editor windows across monitors.
        / The problem is not hardware acceleration, which is supported,
          but rather raising the clock speed from its default slow setting.
        - Nouveau simply cannot (yet) accelerate (raise the clock speed of) a 1030 GPU.
            : see https://www.reddit.com/r/Gentoo/comments/wx9524/enabling_hardware_acceleration_on_nvidia_1070/
            : see https://wiki.archlinux.org/title/Hardware_video_acceleration :
              ‘GPUs up until GeForce GTX 750 are supported’
        - A fix is coming, but I think it will only apply to newer GPUs.
            : see https://www.phoronix.com/news/Nouveau-Linux-6.2-Big-Update
    ! Toggled off then on again, monitors LLL and R come up stuck in a suspended state.
        - Enabling the "DPMS" option for all monitors did not help.
            : re `"DPMS" option` see /etc/X11/Nouveau.conf.d/60_monitors.conf
        - My workaround is to 1) switch from X to a virtual terminal, e.g. by Ctrl-Alt-F1;
          2) toggle LLL and LL off/on (here both come fully on);
          3) do the same for R and RRR; then 4) switch back to X, e.g. Alt-F11.
            / Oddly when the power switch of LLL or R is pressed outside of X, turning it off or on,
              its twin on the same video card (LL or RRR) goes through some kind of reset.
    firmware
        : see https://wiki.gentoo.org/wiki/Linux_firmware
        : see https://wiki.gentoo.org/wiki/Nouveau#Firmware
        - firmware is mandatory (for Nouveau) to drive my Nvidia 1030 GPUs
            : private
                : e.g. `^^FW_LOADER` @ /usr/src/linux/.config.brec
                : e.g. `^^sys-kernel/linux-firmware$` @ /var/lib/portage/world.brec
                : e.g. `^^sys-kernel/linux-firmware$` @ /var/lib/portage/world.brec
            : see https://wiki.gentoo.org/wiki/Linux_firmware :
              ‘Modern graphics cards from AMD and NVIDIA almost certainly require [firmware] to be loaded
               for the hardware to operate correctly.’
        - with firmware packages installed, Nouveau reports the absence of only one type of firmware
            / from `dmesg`, for example:

                  [5.335539] nouveau 0000:09:00.0: NVIDIA GP108 (138000a1)
                  [5.456613] nouveau 0000:09:00.0: bios: version 86.08.24.00.23
                  [5.456689] nouveau 0000:09:00.0: pmu: firmware unavailable
                  [5.457033] nouveau 0000:09:00.0: fb: 2048 MiB GDDR5

        - with firmware packages *un*installed
            - video fails
            - Nouveau reports the absence of *multiple* types of firmware
              followed by a failed hardware probe
            / from `dmesg`, for example:

                  [3.966242] nouveau 0000:04:00.0: NVIDIA GP108 (138000a1)
                  [4.136876] nouveau 0000:04:00.0: bios: version 86.08.24.00.23
                  [4.136930] nouveau 0000:04:00.0: acr: firmware unavailable
                  [4.136931] nouveau 0000:04:00.0: pmu: firmware unavailable
                  [4.136962] nouveau 0000:04:00.0: gr: firmware unavailable
                  [4.136966] nouveau 0000:04:00.0: sec2 ctor failed: -38
                  [4.136970] nouveau: probe of 0000:04:00.0 failed with error -38

    Nvidia to Nouveau, porting the video driver from
        : see @ /etc/X11/README.brec