[AG-TECH] UBUNTU 9.10, VIC, webcam (driver pb ?)

[Christoph Willing]

On 09/12/2009, at 10:18 PM, Marcolino PIRES wrote:

> Hello,
>
>     The problem seems to be solved. Thanks a lot.

Thats good to hear.


>     Can you tell us what was exactly the problem ?

Many webcams rely on the uvcvideo kernel module for their operation  
with Linux. This driver is still being actively developed, with new  
features being added with each kernel release. Occasionally the driver  
improvements introduce new behaviours which require applications to  
change the way in which they interact with the driver module - thats  
what has happened in this case.

When vic first starts up it probes video devices, including running an  
open(), to see if they are available and determine some of their  
characteristics - this is how vic supplies a list of available devices  
for the user to choose from. When a device is chosen, it is reopened  
to start its video stream. With the uvcvideo module that is part of  
kernel 2.6.31.x, the first open() leaves the device in a state that  
makes the second open() problematic. For now, the solution is for vic  
to fully close the device after the first open().


chris


> Christoph Willing a écrit :
>>
>> We have a new vic with a fix for the webcam issue (thanks to Doug  
>> Kosovich of UQVislab). It has been only lightly tested so please  
>> report any problems with it.
>>
>> If the UQVislab repo is enabled on your system (as it probably is,  
>> if you're running AG in Ubuntu), the new vic package can be  
>> installed with the commands:
>>     sudo apt-get update
>>     sudo apt-get upgrade
>>
>> or you could use Synaptic or the Update Manager if you prefer a gui.
>>
>> Please note that for Ubuntu users this fix is only required for  
>> 9.10 (Karmic Koala), due to the recency of the kernel version it  
>> uses. There is no new ag-vic package available nor needed for  
>> earlier Ubuntu releases.
>>
>>
>> chris
>>
>>
>> On 07/12/2009, at 6:44 PM, Philippe d'Anfray wrote:
>>
>>> Bonjour
>>>
>>> Ouf ! I'm not the only one... :-)   I was thinking of "going back"  
>>> to
>>> ubuntu 9.04
>>> now it seems to be the only thing to do for the  time being.
>>>
>>> Merci
>>>
>>> Philippe
>>>
>>> Christoph Willing a écrit :
>>>>
>>>>
>>>> We've now been able to replicate your problem with another webcam  
>>>> that
>>>> is usually "well behaved". At the moment it looks related to the
>>>> kernel version since a particular version of vic that works fine  
>>>> with
>>>> this webcam and kernel series 2.6.29 does not work with the 2.6.31
>>>> series kernel.
>>>>
>>>> Maybe vic will need some modification to adapt to the newer  
>>>> kernels.
>>>> We'll let you know when there is some progress. Until then, the  
>>>> only
>>>> immediate solutions I can think of are:
>>>>  1. revert to an earlier version of your distro (which contains an
>>>> earlier kernel version), e.g. karmic->jaunty
>>>> or
>>>>  2. install an earlier kernel version, e.g. 2.6.31.* -> 2.6.29.6
>>>>
>>>
>>> <Philippe_d-Anfray.vcf>
>>
>> Christoph Willing                       +61 7 3365 8316
>> QCIF Access Grid Manager
>> University of Queensland
>>
>>
>
>
> -- 
> Marcolino PIRES
> Téléphone : 01 44 62 45 73
>
> Rectorat de l'académie de Paris
> CAPTI - Bureau 382
> 94, avenue Gambetta
> 75984 PARIS CEDEX 20
>
> Nonidi 19 Frimaire an CCXVIII, jour de la sabine.

Christoph Willing                       +61 7 3365 8316
QCIF Access Grid Manager
University of Queensland