我有两台笔记本电脑，当我将其中一台连接到投影仪时，它们表现出相同的行为（也就是说根本没有行为）。我有两条可用的电缆路径可供测试，均产生相同的结果。
联想 w530（迷你显示端口 --> DVI）Ubuntu 18.04
联想 x220（显示端口 --> DVI）Ubuntu 20.04
我尝试了两种不同的 DVI 电缆（每种设置都配有一组合适的适配器）。这是用来测试外接显示器的同一种电缆（好吧，其中一种是，但都不适用于投影仪，所以我没有拖着 15 英尺长的电缆来测试它）。
如果我连接任何外接显示器，我都会得到预期的行为：出现短暂闪烁，第二个显示器出现在“显示”设置区域。相比之下，如果我将任何一台笔记本电脑连接到投影仪，两者都不会发生任何事情。没有闪烁（识别）；显示器没有变化；xrandr 没有显示任何变化。谷歌搜索毫无结果。
我需要做什么才能让它工作？
我能够确认这是数字连接问题。我拼凑并测试了一个 VGA 解决方案，它的表现就像显示器连接一样。
编辑：
我已经包含了来自的输出sudo journalctl --follow：
两台独立的笔记本电脑尝试通过 DVI 电缆连接到 Optoma 投影仪的输出。
第一个运行的是 Ubuntu 18.04。当我用迷你显示端口适配器连接电缆时，我在中间添加了间隙。（最后可能有多余的输出，因为我正在检查投影仪而不是直接看输出。）：
此外，第一台笔记本电脑运行的是特殊驱动程序（第二台笔记本电脑则不是）。软件和更新：
Software & Updates
NVIDIA Corportation: GK107GLM [Quadro K1000M]
This device is using an alternative driver.
Using NVIDIA binary driver - version 340.108 from nvidia-340 (proprietary)
sudo journalctl --follow
-- Logs begin at Sun 2020-06-28 04:15:21 PDT. --
Dec 19 11:56:31 archer dbus-daemon[1795]: [session uid=1000 pid=1795] Activating via systemd: service name='org.freedesktop.Telepathy.AccountManager' unit='telepathy-mission-control-5.service' requested by ':1.89' (uid=1000 pid=2372 comm="telepathy-indicator " label="unconfined")
Dec 19 11:56:31 archer systemd[1771]: Starting Telepathy Mission Control service...
Dec 19 11:56:31 archer dbus-daemon[1795]: [session uid=1000 pid=1795] Successfully activated service 'org.freedesktop.Telepathy.AccountManager'
Dec 19 11:56:31 archer systemd[1771]: Started Telepathy Mission Control service.
Dec 19 11:56:31 archer dbus-daemon[1795]: [session uid=1000 pid=1795] Activating service name='org.freedesktop.Telepathy.Client.Vino' requested by ':1.90' (uid=1000 pid=2376 comm="/usr/lib/telepathy/mission-control-5 " label="/usr/lib/telepathy/mission-control-5 (enforce)")
Dec 19 11:56:31 archer org.freedesktop.Telepathy.Client.Vino[1795]: Unknown option --tube
Dec 19 11:56:31 archer org.freedesktop.Telepathy.Client.Vino[1795]: Run 'vino-server --help' to see a full list of available command line options
Dec 19 11:56:31 archer dbus-daemon[1795]: [session uid=1000 pid=1795] Activated service 'org.freedesktop.Telepathy.Client.Vino' failed: Process org.freedesktop.Telepathy.Client.Vino exited with status 1
Dec 19 11:56:34 archer sudo[2384]: jamesisin : TTY=pts/0 ; PWD=/home/jamesisin ; USER=root ; COMMAND=/bin/journalctl --follow
Dec 19 11:56:34 archer sudo[2384]: pam_unix(sudo:session): session opened for user root by (uid=0)
Dec 19 11:56:36 archer zeitgeist-daemon[2287]: [19:56:36.645847 WARNING] zeitgeist-daemon.vala:127: Unable to parse version info!
Dec 19 11:56:36 archer zeitgeist-datah[2386]: zeitgeist-datahub.vala:227: Unable to get name "org.gnome.zeitgeist.datahub" on the bus!
Dec 19 11:56:47 archer /usr/lib/gdm3/gdm-x-session[1789]: (WW) NVIDIA(GPU-0): Unable to read EDID for display device DFP-1
Dec 19 11:56:47 archer /usr/lib/gdm3/gdm-x-session[1789]: (**) NVIDIA(0): Using HorizSync/VertRefresh ranges from the EDID for display
Dec 19 11:56:47 archer /usr/lib/gdm3/gdm-x-session[1789]: (**) NVIDIA(0): device DFP-1 (Using EDID frequencies has been enabled on
Dec 19 11:56:47 archer /usr/lib/gdm3/gdm-x-session[1789]: (**) NVIDIA(0): all display devices.)
Dec 19 11:56:47 archer /usr/lib/gdm3/gdm-x-session[1789]: (II) NVIDIA(0): Setting mode "DP-0: nvidia-auto-select @800x600 +1920+0 {ViewPortIn=800x600, ViewPortOut=800x600+0+0}"
Dec 19 11:56:47 archer /usr/lib/gdm3/gdm-x-session[1789]: (II) NVIDIA(0): Setting mode "NULL"
Dec 19 11:57:17 archer gnome-software[2408]: enabled plugins: systemd-updates, packagekit-url-to-app, packagekit-refresh, packagekit, fwupd, ubuntuone, packagekit-local, packagekit-refine-repos, os-release, shell-extensions, packagekit-proxy, packagekit-upgrade, packagekit-offline, desktop-categories, appstream, packagekit-refine, odrs, desktop-menu-path, steam, hardcoded-featured, generic-updates, modalias, rewrite-resource, hardcoded-popular, hardcoded-blacklist, packagekit-history, snap, provenance, provenance-license, icons, key-colors, key-colors-metadata
Dec 19 11:57:17 archer gnome-software[2408]: disabled plugins: dpkg, repos, dummy, epiphany
Dec 19 11:57:17 archer dbus-daemon[1058]: [system] Activating via systemd: service name='org.freedesktop.fwupd' unit='fwupd.service' requested by ':1.122' (uid=1000 pid=2408 comm="/usr/bin/gnome-software --gapplication-service " label="unconfined")
Dec 19 11:57:17 archer systemd[1]: Starting Firmware update daemon...
Dec 19 11:57:18 archer fwupd[2430]: 19:57:18:0244 FuPluginUefi kernel efivars support missing: /sys/firmware/efi/efivars
Dec 19 11:57:18 archer dbus-daemon[1058]: [system] Successfully activated service 'org.freedesktop.fwupd'
Dec 19 11:57:18 archer systemd[1]: Started Firmware update daemon.
Dec 19 11:57:18 archer PackageKit[1653]: get-updates transaction /14842_edddaebe from uid 1000 finished with success after 941ms
Dec 19 11:57:18 archer gnome-software[2408]: Only 0 apps for recent list, hiding
Dec 19 11:57:19 archer PackageKit[1653]: resolve transaction /14843_ceaccbcd from uid 1000 finished with success after 516ms
Dec 19 11:57:19 archer gnome-shell[1931]: [AppIndicatorSupport-DEBUG] Registering StatusNotifierItem :1.93/org/ayatana/NotificationItem/software_update_available
Dec 19 11:57:19 archer gnome-shell[1931]: [AppIndicatorSupport-DEBUG] Registering StatusNotifierItem :1.93/org/ayatana/NotificationItem/livepatch
Dec 19 11:57:21 archer PackageKit[1653]: search-file transaction /14844_edbdddcd from uid 1000 finished with success after 1521ms
Dec 19 11:57:21 archer PackageKit[1653]: search-file transaction /14845_aabbecad from uid 1000 finished with success after 601ms
Dec 19 11:57:22 archer PackageKit[1653]: search-file transaction /14846_aecdeaca from uid 1000 finished with success after 557ms
Dec 19 11:57:23 archer PackageKit[1653]: search-file transaction /14847_daadbcbb from uid 1000 finished with success after 578ms
Dec 19 11:57:23 archer PackageKit[1653]: search-file transaction /14848_bebbedeb from uid 1000 finished with success after 555ms
Dec 19 11:57:24 archer PackageKit[1653]: search-file transaction /14849_bebedecc from uid 1000 finished with success after 556ms
Dec 19 11:57:24 archer PackageKit[1653]: search-file transaction /14850_dcbcadac from uid 1000 finished with success after 555ms
Dec 19 11:57:25 archer PackageKit[1653]: search-file transaction /14851_aabcdccd from uid 1000 finished with success after 556ms
Dec 19 11:57:25 archer PackageKit[1653]: search-file transaction /14852_aeebddde from uid 1000 finished with success after 554ms
Dec 19 11:57:26 archer PackageKit[1653]: search-file transaction /14853_eaaaedad from uid 1000 finished with success after 555ms
Dec 19 11:57:27 archer PackageKit[1653]: search-file transaction /14854_cdeaebad from uid 1000 finished with success after 573ms
Dec 19 11:57:27 archer PackageKit[1653]: search-file transaction /14855_eccdedce from uid 1000 finished with success after 557ms
Dec 19 11:57:28 archer PackageKit[1653]: search-file transaction /14856_adbaedec from uid 1000 finished with success after 560ms
Dec 19 11:57:28 archer PackageKit[1653]: search-file transaction /14857_adddedab from uid 1000 finished with success after 556ms
Dec 19 11:57:29 archer PackageKit[1653]: search-file transaction /14858_bedcdbda from uid 1000 finished with success after 570ms
Dec 19 11:57:30 archer PackageKit[1653]: search-file transaction /14859_eaeedccd from uid 1000 finished with success after 572ms
Dec 19 11:57:30 archer PackageKit[1653]: search-file transaction /14860_adbdabdb from uid 1000 finished with success after 578ms
Dec 19 11:57:31 archer PackageKit[1653]: search-file transaction /14861_dcbaaeea from uid 1000 finished with success after 579ms
Dec 19 11:57:31 archer PackageKit[1653]: search-file transaction /14862_dbeaabad from uid 1000 finished with success after 554ms
Dec 19 11:57:32 archer PackageKit[1653]: search-file transaction /14863_cacdbced from uid 1000 finished with success after 571ms
Dec 19 11:57:32 archer PackageKit[1653]: search-file transaction /14864_bedbdcbe from uid 1000 finished with success after 573ms
Dec 19 11:57:33 archer PackageKit[1653]: search-file transaction /14865_ebacceea from uid 1000 finished with success after 576ms
Dec 19 11:57:34 archer PackageKit[1653]: get-details transaction /14866_cdaadbda from uid 1000 finished with success after 524ms
Dec 19 11:57:34 archer gnome-software[2408]: Failed to load snap icon: local snap has no icon
Dec 19 11:57:34 archer gnome-software[2408]: Failed to load snap icon: local snap has no icon
Dec 19 11:57:36 archer gnome-software[2408]: Failed to load snap icon: local snap has no icon
Dec 19 11:57:37 archer gnome-software[2408]: Failed to load snap icon: local snap has no icon
Dec 19 11:57:37 archer gnome-software[2408]: Failed to load snap icon: local snap has no icon
Dec 19 11:57:37 archer gnome-software[2408]: Failed to load snap icon: local snap has no icon
Dec 19 11:57:37 archer gnome-software[2408]: Failed to load snap icon: local snap has no icon
Dec 19 11:57:38 archer gnome-software[2408]: ignoring non-installed app GsApp: [0x7efcec10b820]
kind: desktop
state: available
quirk: provenance
id: org.kde.marble
unique-id: system/package/ubuntu-bionic-universe/desktop/org.kde.marble/*
scope: system
bundle-kind: package
kudos: my-language|hi-dpi-icon
kudo-percentage: 40
name: KDE Marble
pixbuf: 0x7efcf01a4d80
icon-kind: stock
icon-name: marble
icon-prefix: /var/lib/app-info/icons/ubuntu-bionic-universe
icon-kind: cached
icon-name: marble_marble.png
icon-prefix: /var/lib/app-info/icons/ubuntu-bionic-universe
icon-kind: remote
version: 4:17.12.3-0ubuntu1
summary: Navigation and Maps
description: Marble is a generic geographical map widget and framework for KDE applications. The Marble widget shows the earth as a sphere but does not require hardware acceleration. A minimal set of geographical data is included, so it can be used without an internet connection.
This package is part of the KDE education module.
source-00: marble
source-id-00: marble;4:17.12.3-0ubuntu1;amd64;ubuntu-bionic-universe
url{homepage}: http://edu.kde.org/
license: LicenseRef-free=https://www.ubuntu.com/about/about-ubuntu/licensing
license-is-free: yes
management-plugin: packagekit
origin: ubuntu-bionic-universe
origin-appstream: ubuntu-bionic-universe
reviews: 0
provides: 0
install-date: 1
size-installed: unknowable
size-download: 181.4 kB
category: Education
category: Geoscience
category: Geography
category: Science
category: Maps
{GnomeSoftware::Creator}: appstream
^C
第二个运行的是 Ubuntu 20.04（当我使用显示端口适配器连接电缆时，我在中间添加了间隙）：
sudo journalctl --follow
-- Logs begin at Fri 2020-04-24 16:20:06 PDT. --
Dec 19 19:00:54 phoenix sudo[11767]: pam_unix(sudo:session): session closed for user root
Dec 19 19:00:54 phoenix sudo[11801]: jamesisin : TTY=pts/1 ; PWD=/home/jamesisin ; USER=root ; COMMAND=/usr/bin/apt autoremove
Dec 19 19:00:54 phoenix sudo[11801]: pam_unix(sudo:session): session opened for user root by (uid=0)
Dec 19 19:00:55 phoenix sudo[11801]: pam_unix(sudo:session): session closed for user root
Dec 19 19:00:55 phoenix sudo[11829]: jamesisin : TTY=pts/1 ; PWD=/home/jamesisin ; USER=root ; COMMAND=/usr/bin/apt autoclean
Dec 19 19:00:55 phoenix sudo[11829]: pam_unix(sudo:session): session opened for user root by (uid=0)
Dec 19 19:00:55 phoenix sudo[11829]: pam_unix(sudo:session): session closed for user root
Dec 19 19:01:03 phoenix systemd[1]: zsysd.service: Succeeded.
Dec 19 19:01:25 phoenix sudo[12005]: jamesisin : TTY=pts/0 ; PWD=/home/jamesisin ; USER=root ; COMMAND=/usr/bin/journalctl --follow
Dec 19 19:01:25 phoenix sudo[12005]: pam_unix(sudo:session): session opened for user root by (uid=0)
Dec 19 19:01:35 phoenix kernel: i915 0000:00:02.0: HDMI-A-1: EDID is invalid:
Dec 19 19:01:35 phoenix kernel: [00] BAD 00 ff ff ff ff ff ff 00 3e 8d 48 33 ae 04 00 00
Dec 19 19:01:35 phoenix kernel: [00] BAD 35 0f 01 03 80 00 00 78 0a 64 fe a4 59 4e a7 22
Dec 19 19:01:35 phoenix kernel: [00] BAD 12 4b 50 af de 00 31 59 3b d9 45 59 61 59 81 80
Dec 19 19:01:35 phoenix kernel: [00] BAD 01 01 01 01 01 01 2f 0d 50 f0 30 e0 25 10 10 70
Dec 19 19:01:35 phoenix kernel: [00] BAD 68 00 00 00 00 00 00 18 00 00 00 ff 00 4f 38 31
Dec 19 19:01:35 phoenix kernel: [00] BAD 47 35 35 33 41 31 31 39 38 0a 00 00 00 fc 00 4f
Dec 19 19:01:35 phoenix kernel: [00] BAD 70 74 6f 6d 61 20 48 33 31 0a 20 20 00 00 00 fd
Dec 19 19:01:35 phoenix kernel: [00] BAD 00 2b 55 10 45 11 00 0a 20 20 20 20 20 20 a1 ff
^C