Bug 446607

Until recently (I don't know for how long) my Logitech, Inc. Webcam C270 worked just fine, but I presume after an update it shows only a black screen in cheese in guvcview.

My lsusb is:
Bus 002 Device 002: ID 8087:8000 Intel Corp. 
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 8087:8008 Intel Corp. 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 003 Device 006: ID 2001:b300 D-Link Corp. 
Bus 003 Device 003: ID 05e3:0612 Genesys Logic, Inc. Hub
Bus 003 Device 007: ID 046d:0825 Logitech, Inc. Webcam C270
Bus 003 Device 005: ID 0458:0178 KYE Systems Corp. (Mouse Systems) 
Bus 003 Device 004: ID 046d:c31c Logitech, Inc. Keyboard K120
Bus 003 Device 002: ID 0424:2514 Microchip Technology, Inc. (formerly SMSC) USB 2.0 Hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub


guvcview is: 

GUVCVIEW: version 2.0.6
V4L2_CORE: (UVCIOC_CTRL_MAP) Error: No such file or directory
V4L2_CORE: (UVCIOC_CTRL_MAP) Error: No such file or directory
V4L2_CORE: (UVCIOC_CTRL_MAP) Error: No such file or directory
V4L2_CORE: (UVCIOC_CTRL_MAP) Error: No such file or directory
V4L2_CORE: (UVCIOC_CTRL_MAP) Error: No such file or directory
V4L2_CORE: (UVCIOC_CTRL_MAP) Error: No such file or directory
V4L2_CORE: (UVCIOC_CTRL_MAP) Error: No such file or directory
V4L2_CORE: (UVCIOC_CTRL_MAP) Error: No such file or directory
V4L2_CORE: (UVCIOC_CTRL_MAP) Error: No such file or directory
ALSA lib pcm_dsnoop.c:641:(snd_pcm_dsnoop_open) unable to open slave
ALSA lib pcm_dmix.c:1089:(snd_pcm_dmix_open) unable to open slave
ALSA lib pcm.c:2642:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear
ALSA lib pcm.c:2642:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe
ALSA lib pcm.c:2642:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
ALSA lib pcm_oss.c:377:(_snd_pcm_oss_open) Unknown field port
ALSA lib pcm_oss.c:377:(_snd_pcm_oss_open) Unknown field port
ALSA lib pcm_usb_stream.c:486:(_snd_pcm_usb_stream_open) Invalid type for card
ALSA lib pcm_usb_stream.c:486:(_snd_pcm_usb_stream_open) Invalid type for card
ALSA lib pcm_dmix.c:1089:(snd_pcm_dmix_open) unable to open slave
Cannot connect to server socket err = No such file or directory
Cannot connect to server request channel
jack server is not running or cannot be started
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
JackShmReadWritePtr::~JackShmReadWritePtr - Init not done for -1, skipping unlock
V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable
V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable
V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable
V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable
V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable
V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable
V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable
V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable
V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable
V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable
V4L2_CORE: Could not grab image (select timeout): Resource temporarily unavailable