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Re: [pwc] VIDIOCPWCRUSER

To: Philips Webcam Linux Driver <>
Subject: Re: [pwc] VIDIOCPWCRUSER
From: Andrew Cavers <>
Date: Fri, 13 Jan 2006 11:01:07 +0000
Tom, Luc, List,

I use PDP with a pwc camera (a Quickcam Pro 4000)  and also had
problems when using the new driver. I found the problem to be with PDP
using specific parts of the old driver that do not exist in Luc's. To
fix the problem I changed the PDP source to remove all pwc references.
This seems to make PDP treat my camera like any other webcam and it
works perfectly. I've copied the email I sent regarding this to the PD
mailing list last year below:

Ok - problem solved. Here's what I did. It should be of use to other
users of PDP with PWC-based webcams too.

1. Download the PDP 0.12.4 source from
http://zwizwa.fartit.com/pd/pdp/pdp-0.12.4.tar.gz

2. In the modules/image_io/pdp_v4l.c file, change the following:
 - Comment out (by adding // to the start of the line) lines 49-52,
188-247 and 488-489.
 - Edit lines 781 and 782 with your preferred default width and
height. I don't think you'll need to change this but I only want to
use 160x120.

3. ./configure (with any options); make; make install

My Logitech Quickcam Pro 4000 works like a dream now with the most
recent reverse-engineered open source PWC driver (10.0.7a) from
http://www.saillard.org/linux/pwc/

It seems like the problem was that PDP was using very specific
features from the old pwc/pwcx driver that are no longer compatible
with the new reverse-engineered driver. Is Tom still updating PDP? I
think that this should be changed in the next release, or at least
commented on in the readme.

Anyway, hope this helps some people.
Ok - problem solved. Here's what I did. It should be of use to other
users of PDP with PWC-based webcams too.

1. Download the PDP 0.12.4 source from
http://zwizwa.fartit.com/pd/pdp/pdp-0.12.4.tar.gz

2. In the modules/image_io/pdp_v4l.c file, change the following:
 - Comment out (by adding // to the start of the line) lines 49-52,
188-247 and 488-489.
 - Edit lines 781 and 782 with your preferred default width and
height. I don't think you'll need to change this but I only want to
use 160x120.

3. ./configure (with any options); make; make install

My Logitech Quickcam Pro 4000 works like a dream now with the most
recent reverse-engineered open source PWC driver (10.0.7a) from
http://www.saillard.org/linux/pwc/

It seems like the problem was that PDP was using very specific
features from the old pwc/pwcx driver that are no longer compatible
with the new reverse-engineered driver. Is Tom still updating PDP? I
think that this should be changed in the next release, or at least
commented on in the readme.

Anyway, hope this helps some people.

On 1/13/06,  <> wrote:
> > > yesterday i found out that if i remove the ioctl to VIDIOCPWCRUSER 
> > > everything
> > > works like normal. so it seems this is a problem with PWC.
> >
> > I don't understand your bug report ... is it a bug or a normal feature ?
>
> that's the question :)
>
> > pwc driver don't call the restore setting, it's the application that use it.
>
> indeed.
> i'm the author of PDP (http://zwizwa.goto10.org/pd/pdp) and Packet
> Forth (http://zwizwa.goto10.org/darcs/libpf)
> both have pwc support, and for newer cameras there's a strange behaviour..
>
> let me be more specific: i have 2 cameras.
> (A) Philips PCVC730K (ToUCam Fun)/PCVC830 (ToUCam II)
> (B) Logitech QuickCam 4000 Pro USB
>
> camera (A) works perfectly for all the versions of pwc that i've used,
> from somewhere around 8.x upto and including the newest version
> 10.0.11-unofficial.
>
> camera (B) seems to not like the VIDIOCPWCRUSER ioctl. more specifically,
> if i call this ioctl after opening the device for the 2nd time 
> (open-close-open),
> every 2 seconds there is a 'flash' in the image, after which the AGC 
> oscillates
> for a moment and the image becomes stable again.
>
> this behaviour for camera (B) has been there since 9.0, which is the lowest 
> version
> i used that supports camera (B).
>
> now, this behaviour occurs only after the video device is opened/closed once.
> unplugging the camera, or unloading/reloading the module seems to reset
> the behaviour, in which case the VIDIOCPWCRUSER seems to work without 
> problems.
>
> > So perhaps it's a problem in your application.
>
> maybe. if so, i don't know what i'm doing wrong.
> i had a look at the pwc-ctrl.c driver source, and it seems the IOCTL
> implementation is fairly simple, so i can't imagine anything being wrong
> with that.
>
>
> i've also had this report from a Packet Forth user:
>
> | I got myself a webcam connected to my machine. It's a "Logitech
> | Quickcam for Notebooks Pro".  Works wonderful!
> | There's also a little bit of weird behavior with this, since it's
> | resetting the exposure of my webcam every second or so (goes dark for
> | about three frames). Not the same in xawtv or effectv...
>
> which seems to be the same behaviour as my camera (B)
>
> my v4l code is in v4l.c at
> http://zwizwa.goto10.org/darcs/libpf/plugins/v4l/
>
> you can try for yourself:
>
> wget http://zwizwa.goto10.org/darcs/libpf/libpf.tar.gz
> tar zxf libpf.tar.gz
>
>         ( change the if(1) to if(0) in libpf/plugins/v4l/v4l.c on line 226
>           see also line 201 )
>
> cd libpf
> . bootstrap
> mkdir d
> cd d
> ../configure --enable-debug
> make local
>
>
> bin/pf ../demo/tv.pf
> bye
> bin/pf ../demo/tv.pf
>
>
> the second time you run it should produce the bug.
>
> hope this helps
> tom
>
> _______________________________________________
> pwc mailing list
> 
> http://lists.saillard.org/mailman/listinfo/pwc
>


--
--
Andrew Cavers

www.mution.com
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