Hello Laurent
> On Wednesday 20 May 2009 05:29:27 bruce m beach wrote:
>
> > Okay. Here's what I have done to the code in luvcview ...
> > ... ...
> > ... ...
> > uvcGrab: ret=ioctl(vd->fd, VIDIOC_DQBUF, &vd->buf); (BEFORE THE CALL):
> > ... ... ^^^^^^ ^^^ ^^^^
> > camera data by whatever method). The call is completed once, some other
> > stuff is executed, it is entered again, calls
> >
> > ret=ioctl(vd->fd, VIDIOC_DQBUF, &vd->buf)
> >
> > and never returns. It stays in the call until kill -9 luvcview(PID)
> > is executed.
> > ... ... One question is why doesn't it time out?
>
> The V4L2 specification doesn't specify if and when VIDIOC_DQBUF should
> timeout. Why would you like it to timeout ?
>
Maybe it shouldn't timeout, but some kind of check should be made
in userland. A common complaint on the web is that programs (including
luvcview) do not respond to normal program exit or "cntrl-C". The
only way to terminate is "kill -9 pid". I believe that if something
goes wrong and the camera doesn't start streaming then it gets stuck
in this ioctl(VIDIOC_DQBUF) and waits forerever. The capture example
from the uvc api uses "select" to monitor buffers and dies with
sh-4.0# capture_example
select timeout
and I believe mplayer also uses the same mechanism
sh-4.0# mplayer tv://
Starting playback...
v4l2: select timeout
v4l2: select timeout ??% ??,?% 0 0
v4l2: select timeout ??% ??,?% 0 0
v4l2: select timeout ??% ??,?% 0 0
v4l2: 1 frames successfully processed, 0 frames dropped.
Exiting... (Quit)
> > I have another webcam (0c45:6009 Microdia VideoCAM ExpressII) that uses
> > "modprobe sn9c102" to work. If I run it with luvcview it is only gives
> > a green screen but the uvcGrab looping works and it terminates normally.
> > I have another program (sn-webcam) where the ExpressII works okay.
> That's a completely different driver, and I'm not familiar with it, sorry.
My interest in it was that it wasn't getting stalled int the VIDIOC_DQBUF
ioctl call. I'm not clear what should work and what shouldn't work with
luvcview. Given that everything was working properly and I used a camera
using the sn9c102 driver which of the 3 possiblilities would you pick
1) Definitely should work
2) Not in a million years.
3) Might work depending on whatever it depends on.
> > By the way doing "make" on luvcview gives a lot of redefinitions like: ...
> I assume you get those warnings with the deprecated SVN version.
> Don't use it, it's really deprecated.
Good thing I mentioned it then. I went to
http://svn.quickcamteam.net/svn/luvcview/trunk/luvcview/
which I assume is the current version. It compiles without the warnings
and seems to work a little bit better.
> The reason why VIDIOC_DQBUF fails to return is probably that the driver
> doesn't get enough data from the camera to fill a frame (or that it believes
> it doesn't).
One question is after the first frame does it get any data at all
and is ioctl(VIDIOC_STREAMON) really happening.
>Could you set the trace level to 255, run luvcview for a few
> seconds, kill it
> (ctrl-\ should do the job)
Never saw this one before but it works. Live and learn.
> and send me the messages printed by the uvcvideo driver to the kernel log ?
Okay. I insert the following messages in the kernel log at the
approprate times
MESSAGE modprobe uvcvideo trace=255
MESSAGE starting luvcvideo
MESSAGE cntrl backslash
MESSAGE done
here is the output from luvcview
sh-4.0# luvcview
luvcview 0.2.5
SDL information:
Video driver: x11
A window manager is available
Device information:
Device path: /dev/video0
Stream settings:
Frame format: MJPG
Frame size: 640x480
Frame rate: 30 fps
^\Quit
and below is the output from the kernel log.
Bruce
MESSAGE modprobe uvcvideo trace=255
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Brightness
to control 00000000-0000-0000-0000-000000000101/2.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Contrast
to control 00000000-0000-0000-0000-000000000101/3.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Hue to
control 00000000-0000-0000-0000-000000000101/6.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Saturation
to control 00000000-0000-0000-0000-000000000101/7.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Sharpness
to control 00000000-0000-0000-0000-000000000101/8.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Gamma to
control 00000000-0000-0000-0000-000000000101/9.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Backlight
Compensation to control 00000000-0000-0000-0000-000000000101/1.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Gain to
control 00000000-0000-0000-0000-000000000101/4.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Power Line
Frequency to control 00000000-0000-0000-0000-000000000101/5.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Hue, Auto
to control 00000000-0000-0000-0000-000000000101/16.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Exposure,
Auto to control 00000000-0000-0000-0000-000000000001/2.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Exposure,
Auto Priority to control 00000000-0000-0000-0000-000000000001/3.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Exposure
(Absolute) to control 00000000-0000-0000-0000-000000000001/4.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping White
Balance Temperature, Auto to control
00000000-0000-0000-0000-000000000101/11.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping White
Balance Temperature to control
00000000-0000-0000-0000-000000000101/10.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping White
Balance Component, Auto to control
00000000-0000-0000-0000-000000000101/13.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping White
Balance Blue Component to control
00000000-0000-0000-0000-000000000101/12.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping White
Balance Red Component to control
00000000-0000-0000-0000-000000000101/12.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Focus
(absolute) to control 00000000-0000-0000-0000-000000000001/6.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Focus,
Auto to control 00000000-0000-0000-0000-000000000001/8.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Zoom,
Absolute to control 00000000-0000-0000-0000-000000000001/11.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Zoom,
Continuous to control 00000000-0000-0000-0000-000000000001/12.
May 28 10:52:28 lapsystemx kernel: uvcvideo: Adding mapping Privacy to
control 00000000-0000-0000-0000-000000000001/17.
May 28 10:52:28 lapsystemx kernel: uvcvideo 4-1:1.0: usb_probe_interface
May 28 10:52:28 lapsystemx kernel: uvcvideo 4-1:1.0:
usb_probe_interface - got id
May 28 10:52:28 lapsystemx kernel: uvcvideo: Probing generic UVC device 1
May 28 10:52:28 lapsystemx kernel: uvcvideo: Found format MJPEG.
May 28 10:52:28 lapsystemx kernel: uvcvideo: - 640x480 (30.0 fps)
May 28 10:52:28 lapsystemx kernel: uvcvideo: - 352x288 (30.0 fps)
May 28 10:52:28 lapsystemx kernel: uvcvideo: - 320x240 (30.0 fps)
May 28 10:52:28 lapsystemx kernel: uvcvideo: - 176x144 (30.0 fps)
May 28 10:52:28 lapsystemx kernel: uvcvideo: - 160x120 (30.0 fps)
May 28 10:52:28 lapsystemx kernel: uvcvideo: Found a Status endpoint (addr 83).
May 28 10:52:28 lapsystemx kernel: uvcvideo: Found UVC 1.00 device
Crystal Eye webcam (064e:a103)
May 28 10:52:28 lapsystemx kernel: uvcvideo: Added control
00000000-0000-0000-0000-000000000101/2 to device 1 entity 3
May 28 10:52:28 lapsystemx kernel: uvcvideo: Added control
00000000-0000-0000-0000-000000000101/3 to device 1 entity 3
May 28 10:52:28 lapsystemx kernel: uvcvideo: Added control
00000000-0000-0000-0000-000000000101/6 to device 1 entity 3
May 28 10:52:28 lapsystemx kernel: uvcvideo: Added control
00000000-0000-0000-0000-000000000101/7 to device 1 entity 3
May 28 10:52:28 lapsystemx kernel: uvcvideo: Added control
00000000-0000-0000-0000-000000000101/8 to device 1 entity 3
May 28 10:52:28 lapsystemx kernel: uvcvideo: Added control
00000000-0000-0000-0000-000000000101/9 to device 1 entity 3
May 28 10:52:28 lapsystemx kernel: uvcvideo: Added control
00000000-0000-0000-0000-000000000101/12 to device 1 entity 3
May 28 10:52:28 lapsystemx kernel: uvcvideo: Added control
00000000-0000-0000-0000-000000000101/1 to device 1 entity 3
May 28 10:52:28 lapsystemx kernel: uvcvideo: Added control
00000000-0000-0000-0000-000000000101/5 to device 1 entity 3
May 28 10:52:28 lapsystemx kernel: uvcvideo: Added control
00000000-0000-0000-0000-000000000101/13 to device 1 entity 3
May 28 10:52:28 lapsystemx kernel: uvcvideo: Scanning UVC chain: OT 2
<- XU 5 <- XU 4 <- PU 3 <- IT 1
May 28 10:52:28 lapsystemx kernel: uvcvideo: Found a valid video chain (1 -> 2).
May 28 10:52:28 lapsystemx kernel: input: Crystal Eye webcam as
/class/input/input8
May 28 10:52:28 lapsystemx kernel: uvcvideo: UVC device initialized.
May 28 10:52:28 lapsystemx kernel: usbcore: registered new interface
driver uvcvideo
May 28 10:52:28 lapsystemx kernel: USB Video Class driver (v0.1.0)
MESSAGE starting luvcvideo
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_open
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_QUERYCAP)
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_ENUM_FMT)
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_ENUM_FMT)
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_S_FMT)
May 28 10:53:23 lapsystemx kernel: uvcvideo: Trying format 0x47504a4d
(MJPG): 640x480.
May 28 10:53:23 lapsystemx kernel: uvcvideo: Using default frame
interval 33333.3 us (30.0 fps).
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_S_PARM)
May 28 10:53:23 lapsystemx kernel: uvcvideo: Setting frame interval to
1/30 (333333).
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_G_PARM)
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_REQBUFS)
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_QUERYBUF)
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_mmap
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_QUERYBUF)
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_mmap
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_QUERYBUF)
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_mmap
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_QUERYBUF)
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_mmap
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_QBUF)
May 28 10:53:23 lapsystemx kernel: uvcvideo: Queuing buffer 0.
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_QBUF)
May 28 10:53:23 lapsystemx kernel: uvcvideo: Queuing buffer 1.
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_QBUF)
May 28 10:53:23 lapsystemx kernel: uvcvideo: Queuing buffer 2.
May 28 10:53:23 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_QBUF)
May 28 10:53:23 lapsystemx kernel: uvcvideo: Queuing buffer 3.
May 28 10:53:26 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_STREAMON)
May 28 10:53:26 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_DQBUF)
May 28 10:53:28 lapsystemx kernel: uvcvideo: Frame complete (overflow).
May 28 10:53:28 lapsystemx kernel: uvcvideo: Dropping payload (out of sync).
May 28 10:53:28 lapsystemx last message repeated 18 times
May 28 10:53:28 lapsystemx kernel: uvcvideo: Dequeuing buffer 0 (3,
307789 bytes).
May 28 10:53:28 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_QBUF)
May 28 10:53:28 lapsystemx kernel: uvcvideo: Queuing buffer 0.
May 28 10:53:28 lapsystemx kernel: uvcvideo: uvc_v4l2_ioctl(VIDIOC_DQBUF)
May 28 10:53:28 lapsystemx kernel: uvcvideo: Dropping payload (out of sync).
May 28 10:53:59 lapsystemx last message repeated 30784 times
May 28 10:55:00 lapsystemx last message repeated 60992 times
MESSAGE cntrl backslash
May 28 10:55:24 lapsystemx last message repeated 24351 times
May 28 10:55:24 lapsystemx kernel: uvcvideo: uvc_v4l2_release
MESSAGE done
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