我的 Ubuntu HP 笔记本电脑找不到其摄像头，所以我无法使用视频。
相机显示“未找到设备”没有帮助。
从这个问题开始，
sudo lshw -class video
有输出
*-display
description: VGA compatible controller
product: CometLake-U GT2 [UHD Graphics]
vendor: Intel Corporation
physical id: 2
bus info: pci@0000:00:02.0
logical name: /dev/fb0
version: 02
width: 64 bits
clock: 33MHz
capabilities: pciexpress msi pm vga_controller bus_master cap_list rom fb
configuration: depth=32 driver=i915 latency=0 resolution=1920,1080
resources: irq:142 memory:b2000000-b2ffffff memory:c0000000-cfffffff ioport:5000(size=64) memory:c0000-dffff
*-display
description: 3D controller
product: GP108M [GeForce MX250]
vendor: NVIDIA Corporation
physical id: 0
bus info: pci@0000:02:00.0
version: a1
width: 64 bits
clock: 33MHz
capabilities: pm msi pciexpress bus_master cap_list rom
configuration: driver=nouveau latency=0
resources: irq:141 memory:b3000000-b3ffffff memory:a0000000-afffffff memory:b0000000-b1ffffff ioport:4000(size=128)
我也可以做
lsusb -v | grep Camera
按照建议集成摄像头
给出错误：
Couldn't open device, some information will be missing
Couldn't open device, some information will be missing
Couldn't open device, some information will be missing
Couldn't open device, some information will be missing
Couldn't open device, some information will be missing
Couldn't open device, some information will be missing
输出lsusb非常巨大，为了简洁起见我不想在这里放那么多信息。
当我启动时cheese，终端上出现以下警告：
** Message: 16:26:26.963: cheese-application.vala:222: Error during camera setup: No device found
(cheese:19569): cheese-CRITICAL **: 16:26:26.972: cheese_camera_device_get_name: assertion 'CHEESE_IS_CAMERA_DEVICE (device)' failed
(cheese:19569): GLib-CRITICAL **: 16:26:26.972: g_variant_new_string: assertion 'string != NULL' failed
(cheese:19569): GLib-CRITICAL **: 16:26:26.972: g_variant_ref_sink: assertion 'value != NULL' failed
(cheese:19569): GLib-GIO-CRITICAL **: 16:26:26.972: g_settings_schema_key_type_check: assertion 'value != NULL' failed
(cheese:19569): GLib-CRITICAL **: 16:26:26.972: g_variant_get_type_string: assertion 'value != NULL' failed
(cheese:19569): GLib-GIO-CRITICAL **: 16:26:26.972: g_settings_set_value: key 'camera' in 'org.gnome.Cheese' expects type 's', but a GVariant of type '(null)' was given
(cheese:19569): GLib-CRITICAL **: 16:26:26.972: g_variant_unref: assertion 'value != NULL' failed
** (cheese:19569): CRITICAL **: 16:26:26.972: cheese_preferences_dialog_setup_resolutions_for_device: assertion 'device != NULL' failed
关于屏幕显示以下系统信息：
还有lspci列表
00:00.0 Host bridge: Intel Corporation Comet Lake-U v1 4c Host Bridge/DRAM Controller (rev 0c)
00:02.0 VGA compatible controller: Intel Corporation CometLake-U GT2 [UHD Graphics] (rev 02)
00:04.0 Signal processing controller: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Thermal Subsystem (rev 0c)
00:08.0 System peripheral: Intel Corporation Xeon E3-1200 v5/v6 / E3-1500 v5 / 6th/7th/8th Gen Core Processor Gaussian Mixture Model
00:12.0 Signal processing controller: Intel Corporation Comet Lake Thermal Subsytem
00:14.0 USB controller: Intel Corporation Comet Lake PCH-LP USB 3.1 xHCI Host Controller
00:14.2 RAM memory: Intel Corporation Comet Lake PCH-LP Shared SRAM
00:14.3 Network controller: Intel Corporation Comet Lake PCH-LP CNVi WiFi
00:14.5 SD Host controller: Intel Corporation Comet Lake PCH-LP SCS3
00:15.0 Serial bus controller: Intel Corporation Serial IO I2C Host Controller
00:15.1 Serial bus controller: Intel Corporation Comet Lake Serial IO I2C Host Controller
00:16.0 Communication controller: Intel Corporation Comet Lake Management Engine Interface
00:17.0 RAID bus controller: Intel Corporation 82801 Mobile SATA Controller [RAID mode]
00:1c.0 PCI bridge: Intel Corporation Comet Lake PCI Express Root Port #1 (rev f0)
00:1c.4 PCI bridge: Intel Corporation Comet Lake PCI Express Root Port #5 (rev f0)
00:1d.0 PCI bridge: Intel Corporation Comet Lake PCI Express Root Port #9 (rev f0)
00:1d.4 PCI bridge: Intel Corporation Comet Lake PCI Express Root Port #13 (rev f0)
00:1f.0 ISA bridge: Intel Corporation Comet Lake PCH-LP LPC Premium Controller/eSPI Controller
00:1f.3 Multimedia audio controller: Intel Corporation Comet Lake PCH-LP cAVS
00:1f.4 SMBus: Intel Corporation Comet Lake PCH-LP SMBus Host Controller
00:1f.5 Serial bus controller: Intel Corporation Comet Lake SPI (flash) Controller
02:00.0 3D controller: NVIDIA Corporation GP108M [GeForce MX250] (rev a1)
03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15)
04:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD Controller 980
我怎样才能让我的相机/网络摄像头再次工作？
答案1
我在同一台笔记本电脑上登录 Windows，发现相机也无法使用。在网上搜索后，我发现首先要检查的是是否有关闭相机的开关。
这台笔记本电脑上就有这样的开关。我移动了开关，Ubuntu 分区又有了可用的摄像头。
我真傻。