Re: [Motion-user] Error on Bttv card or camera?

[Angel C. <ac...@te...>]

El dom, 16-11-2008 a las 22:15 +0100, AlexW escribió:
> Alberto Garcia schrieb:
> > Hi all,

Hi Guys,


> > from yesterday, at any moment one of my camera (8 total) is going down and the 
> > system log show this:
> >
> > Nov 16 15:45:25 kernel: bttv7: timeout: drop=1 irq=702206/1534158, 
> > risc=37dd503c, bits: HSYNC OFLOW
> > Nov 16 15:45:25 motion: [3] v4l2_next: VIDIOC_DQBUF: EIO (s->pframe 0)
> > Nov 16 15:45:25 kernel: bttv7: reset, reinitialize
> > Nov 16 15:45:25 motion: [3] v4l2_next: VIDIOC_DQBUF: EIO (s->pframe 1)
> > Nov 16 15:45:25 motion: [3] v4l2_next: VIDIOC_DQBUF: EIO (s->pframe 2)
> > Nov 16 15:45:25 kernel: bttv7: PLL: 28636363 => 35468950 . ok
> > Nov 16 15:45:25 motion: [3] v4l2_next: VIDIOC_DQBUF: EIO (s->pframe 3)
> > Nov 16 15:45:25 kernel: bttv7: timeout: drop=1 irq=702208/1534201, 
> > risc=37dd503c, bits: HSYNC OFLOW
> >
> > repeat every second....and motion show "Connection to camera lost"
> > Unplugged the power supply or RCA connections is not solution...

According V4L2 Specs EIO error in VIDIOC_DQBUF is :

"failed due to an internal error. Can also indicate temporary problems
like signal loss. Note the driver might dequeue an (empty) buffer
despite returning an error, or even stop capturing"

So we tried to add a workaround in motion , sometimes this is not
working good enough. So the thing is :

Motion tries to dequeue from driver outgoing buffer, but driver returns
EIO because outgoing buffer empty or not yet filled, this could be : 

1-. Because not enough resources to fill buffer at that framerate ?
2-. Signal lost on bttv or buggy driver over bttv ?

Solution ... ignore this EIO and return an error because cannot get an
image from buffer or what i did in an attached patch , ignore this EIO
but don't return a fatal error but set an grey image in stream same we
do for lost connection and retry until we can dequeue from outgoing
buffer.


> > I have a two capture card. The first card (with this problem) is a cheap card 
> > Ebay with 8 chipset 878 and support 6 cameras
> > The other capture card is other Ebay card type Kodicom with 4 chipset 878. and 
> > support 2 cameras.
> >
> > Any idea about where is the problem?¿ 
> >
> > Thank you...
> 
> Hi,
> 
> i use a spectra 8 card with 4 cameras and got the same problem.
> Tried old and newest kernels w/o and with from http://linuxtv.org/hg/v4l-dvb
> but nothing helped for me. Seems an very annoying bug.


Attached a patch against 3.2.11

cd motion-3.2.11/
{copy patch in current directory}
patch -p0 < EIO-workaround.diff 
make ; make install

> BR,
> Alex
> 


Cheers
-- 
Angel Carpintero
ack ( at ) telefonica ( dot ) net

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