GNOME Bugzilla – Bug 782627
Cheese starts slowly
Last modified: 2017-12-06 11:39:28 UTC
Ubuntu 17.04, Cheese 3.24, Logitech USB Webcam C270: Starting cheese, it needs 35s until I see a picture. STRACE shows that cheese is waiting 12s in a futex, and 75% of the time it is doing 3000 ioctls with /dev/video0.
Thanks for your bug report. Can you please try to downgrade the cheese and/or try with older kernel to see if it is caused by some recent cheese changes, or is a bug in kernel?
Just a note that it also affects user-accounts panel of gnome-control-center and Bug 783789 contains various debug info...
*** Bug 783789 has been marked as a duplicate of this bug. ***
I am not able to reproduce the slowdown even with an external webcam, however, it hangs completely with kernel-4.12.0-0.rc6.git3.1.fc27.x86_64 with the following backtrace (kernel-4.11.0-1.fc27.x86_64 works nicely):
+ Trace 237595
Thread 1 (Thread 0x7f55659cfac0 (LWP 5292))
So I suppose this is caused by kernel driver and thus NOTGNOME. Can somebody confirms it?
I'm on f26 and I saw this problem 2 months ago at least (I can't remember when precisely). The current kernel is 4.11.6-301
I'm affected by this problem on Ubuntu Desktop 17.10 with a Logitech 9000 Pro I downgraded cheese from 3.26.0-0ubuntu1 to 3.24.0-0ubuntu1 and the kernel from 4.13 to 4.11 to 4.10 without any difference. IT takes roughly 34s to start with an external webcam and 4s with the internal webcam. Strace shows that during startup cheese spends most of its time repeating this sequence with slight variations each time (fmt.pix differs) 1121 10:16:18.795096 ioctl(20, VIDIOC_ENUM_FRAMESIZES, {index=12, pixel_format=v4l2_fourcc('Y', 'U', 'Y', 'V'), type=V4L2_FRMSIZE_TYPE_DISCRETE, discrete={width=960, height=720}}) = 0 1121 10:16:18.795344 ioctl(20, VIDIOC_ENUM_FRAMEINTERVALS, {index=0, pixel_format=v4l2_fourcc('Y', 'U', 'Y', 'V'), width=960, height=720, type=V4L2_FRMIVAL_TYPE_DISCRETE, discrete=1/15}) = 0 1121 10:16:18.795870 ioctl(20, VIDIOC_ENUM_FRAMEINTERVALS, {index=1, pixel_format=v4l2_fourcc('Y', 'U', 'Y', 'V'), width=960, height=720, type=V4L2_FRMIVAL_TYPE_DISCRETE, discrete=1/10}) = 0 1121 10:16:18.796237 ioctl(20, VIDIOC_ENUM_FRAMEINTERVALS, {index=2, pixel_format=v4l2_fourcc('Y', 'U', 'Y', 'V'), width=960, height=720, type=V4L2_FRMIVAL_TYPE_DISCRETE, discrete=1/5}) = 0 1121 10:16:18.796593 ioctl(20, VIDIOC_ENUM_FRAMEINTERVALS, {index=3, pixel_format=v4l2_fourcc('Y', 'U', 'Y', 'V'), width=960, height=720}) = -1 EINVAL (Invalid argument) 1121 10:16:18.797045 ioctl(20, VIDIOC_CROPCAP, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, bounds={left=0, top=0, width=640, height=480}, defrect={left=0, top=0, width=640, height=480}, pixelaspect=1/1}) = 0 1121 10:16:18.797277 ioctl(20, VIDIOC_TRY_FMT, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_ANY, bytesperline=0, sizeimage=0, colorspace=0 /* V4L2_COLORSPACE_??? */} => fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SRGB}}) = 0 1121 10:16:18.824205 ioctl(20, VIDIOC_TRY_FMT, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SMPTE170M} <unfinished ...> 1091 10:16:18.828646 <... poll resumed> ) = 0 (Timeout) 1091 10:16:18.828905 inotify_add_watch(14, "/home/j-lallement/Vid\303\251os/Webcam", IN_MODIFY|IN_ATTRIB|IN_CLOSE_WRITE|IN_MOVED_FROM|IN_MOVED_TO|IN_CREATE|IN_DELETE|IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|IN_ONLYDIR) = -1 ENOENT (No such file or directory) 1091 10:16:18.829180 poll([{fd=4, events=POLLIN}, {fd=14, events=POLLIN}], 2, 3995 <unfinished ...> 1121 10:16:18.852812 <... ioctl resumed> => fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SRGB}}) = 0 1121 10:16:18.853124 ioctl(20, VIDIOC_TRY_FMT, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SMPTE240M} => fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SRGB}}) = 0 1121 10:16:18.881687 ioctl(20, VIDIOC_TRY_FMT, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_REC709} => fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SRGB}}) = 0 1121 10:16:18.910255 ioctl(20, VIDIOC_TRY_FMT, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_470_SYSTEM_M} => fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SRGB}}) = 0 1121 10:16:18.937660 ioctl(20, VIDIOC_TRY_FMT, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_470_SYSTEM_BG} => fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SRGB}}) = 0 1121 10:16:18.964148 ioctl(20, VIDIOC_TRY_FMT, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_JPEG} => fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SRGB}}) = 0 1121 10:16:18.992298 ioctl(20, VIDIOC_TRY_FMT, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SRGB} => fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SRGB}}) = 0 1121 10:16:19.021039 ioctl(20, VIDIOC_TRY_FMT, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=0x9 /* V4L2_COLORSPACE_??? */} => fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SRGB}}) = 0 1121 10:16:19.048770 ioctl(20, VIDIOC_TRY_FMT, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=0xa /* V4L2_COLORSPACE_??? */} => fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SRGB}}) = 0 1121 10:16:19.077229 ioctl(20, VIDIOC_TRY_FMT, {type=V4L2_BUF_TYPE_VIDEO_CAPTURE, fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=0xb /* V4L2_COLORSPACE_??? */} => fmt.pix={width=960, height=720, pixelformat=v4l2_fourcc('Y', 'U', 'Y', 'V'), field=V4L2_FIELD_NONE, bytesperline=1920, sizeimage=1382400, colorspace=V4L2_COLORSPACE_SRGB}}) = 0 1121 10:16:19.104479 ioctl(20, VIDIOC_ENUM_FRAMESIZES, {index=13, pixel_format=v4l2_fourcc('Y', 'U', 'Y', 'V'), type=V4L2_FRMSIZE_TYPE_DISCRETE, discrete={width=1280, height=720}}) = 0
With Ubuntu 17.10 on Wayland and Cheese 3.26 the Problem disappeared. Do you use Wayland or Xorg?
I tried both and the result is the same. 34s to start with the external camera plugged in.
With gstreamer in debug mode I think the slowness comes from the enumeration of the capabilities of the camera. The external one supporting more format the enumeration is much slower. There is a similar issue with the account settings panel of gnome shell and it's slower to open with the webcam attached and again it's gstreamer spending time probing the video device.
Created attachment 362800 [details] [review] monitor: Implement GAsyncInitable interface Monitor initialization may block if external camera is conbected, probably due to some kernel bug. It causes freezes for applications, which is not acceptable. Let's implement GAsyncInitable interface, so it can be initialized asynchronously.
*** Bug 788749 has been marked as a duplicate of this bug. ***