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 >
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