Thanks Paulo, not only Logitech fails, but also Creative (Optia AF at least). I will get a new Philips soon ... I hope this will work better.
On Fri, 29 May 2009 13:49:55 +0100, Paulo Assis wrote > Javier Hi, > You should know that at least logitech cameras don't handle well usb > hubs, logitech is very clear on this, if you want you can get more > info on the quickcamteam site and forums, it has something to do > with the way data is handled by most usb hubs. Anyway I have been > able to connect up to 3 uvc cameras simultaneously in my pc, and I > believe two of them were on the same host (I mounted the pc myself > so I should know this for sure, but my memory has seen better days :) > ), all of them use the ehci driver. Some drivers are in fact buggy, > just check the following link for a example > (in this case the musb driver): http://forums.quickcamteam.net/showthread.php?tid=821 > > Best regards, > Paulo > > 2009/5/29 Javier Martínez Baena <[email protected]> > > > >Hi Javier, > > > > > >On Friday 22 May 2009 09:36:32 J. Martínez Baena wrote: > > >> Hello, > > > > > >> I have a problem with 2 webcams I'm trying to get work simultaneously. I > > >> have several models (Logitech P3000, Logitech P9000, Creative LiveCAM > > Optia > > >> AF, Philips). When I plug two of them on different USB ports, then > > >> everything works ok: I can see both simultaneously with, for example, > > >> luvcview. > > >> > > >> The problem exists when I plug two of them on the same USB (for example > > on > > >> frontal USB or in a USB hub). I've got the problem for combinations in > > wich > > >> UVC driver is used by both cameras. I can get frames for one of them > > (the > > >> first that I try), but for the second one I get a "noisy/green" screen > > ... > > >> it seems as if the image is corrupted. > > >> > > >> However, if I put the philips and the logitech P9000/Optia it works > > fine. > > >> The Philips (and logitech P3000) use a different driver than UVC. Also, > > I > > >> can plug two philips webcam and they works fine. > > >> > > >> ¿Is this a bug or an unresolved problem of the UVC driver? ¿Is it a USB > > >> problem? > > > > > >My guess is that you're having USB bandwidth issues. As the uvcvideo > > driver > > >starts capturing video on both cameras, you're not exceeding the > > theoretical > > >USB bandwidth limit. However, bugs in the USB host controller, the USB > > host > > >controller driver or the camera can result in corrupted data. Could you > > >perform the same test on another computer ? > > > > > >Best regards, > > > > > >Laurent Pinchart > > > > > > Hi Laurent, > > > > Sorry for the delay ... I make some tests on several computers and the > > problem > > persists. My guess is that is a problem of UVC driver (but I'm not an > > expert > > ... so it's only a guess!). When I connect different webcams (using other > > driver than UVC) it works. > > > > I tried with different resolutions (320x240, 640x480, ...) and different > > framerates. > > > > Sometimes, when a cam is running (capturing), I can't even initialice the > > other one (neither consult for allowed resolutions, etc). > > > > But I don't know how USB driver works, so, maybe an USB problem. > > > > Best regards > > > > > > _______________________________________________ > > Linux-uvc-devel mailing list > > [email protected] > > https://lists.berlios.de/mailman/listinfo/linux-uvc-devel > > -- Dr. Javier Martínez Baena Dpto. Ciencias de la Computación e I. A. E.T.S. de Ingeniería Informática Universidad de Granada Tlf: 958 240802 Fax: 958 243317 Email: [email protected] -- DEpartment of Computer Science and A.I. http://decsai.ugr.es _______________________________________________ Linux-uvc-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
