endless waiting in vidioc_dqbuf

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Posted by Kenzo10099

on Apr 13 2009 22:15 PM

when calling ioctl(fdCapture, VIDIOC_DQBUF, &buf) in CaptureFrame() , my program went into an endless waiting. by debugging , I found that in in video-buf.c , if (vb->state == STATE_ACTIVE || vb->state == STATE_QUEUED) schedule(); my program was blocked here.

Wanna know if there are some possible reasons causing this blocking.

Time is nothing, timing is everything!

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Posted by Bernie Thompson TI

on Apr 16 2009 21:15 PM

Mastermind41680 points

One thought would be if your capture hardware was not receiving a proper clock and syncs meaning it never acknowledges receiving a new frame and so you are queued indefinitely.

Posted by Avneet Dhaliwal

on May 30 2012 05:35 AM

Prodigy130 points

Hi Bernie,

I am facing a similar problem. Can you please elaborate more on your above explanation?

Thanks a lot.

Regards,

Avneet

Posted by sujit mahapatro

on May 31 2012 04:45 AM

Genius3920 points

Just a quick guess, Can you check by changing your polarity.

By the way which kernel and evm you are using.

Posted by Avneet Dhaliwal

on Jun 07 2012 09:56 AM

Prodigy130 points

Hi Sujit,

I am a beginner in this field. I am sorry I didn't understand what you mean by "changing the polarity"??

I am using dvsdk 4.02.00.06 with linux 2.6.32 on DM368.

Regards,

Avneet

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