On Fri, Feb 03, 2006 at 12:23:53AM -0500, Jamaal Speights wrote: > Hello, > > I'm having a problem using two usb PVRs that work under the Video for Linux > Two device driver system. The device i'm using is a KWorld USB PVR which > uses the em28xx drives. When I input the two devices udev creates > /dev/video0 and /dev/video1. I can use each device using mplayer > individual, however using USBview I notice that the bandwidth allocated to > the FIRST USED device is %60 percent. So whenever I try using both devices > at the same time, the first device I call with mplayer, linux will allocate > %60 percent of the USB 2.0 bandwidth to /dev/video0 (in this example). > However when I try capturing from the second device I get "Not enough space > left on device" because the second device probably wants to allocate 60% > bandwidth as well. I've been working with *Markus Rechberger *who is one of > the main em28xx v4l2 driver authors. From his knowledge he states that its > most likely a usb subsytem issue with bandwith allocation. Below are the > technical details
The Linux USB bandwidth reservation code is "interesting" and doesn't always work properly. So for this kind of application I would really recommend using two different USB host controllers to drive the two devices. Then you will not have any problems. Hope this helps, greg k-h ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=103432&bid=230486&dat=121642 _______________________________________________ [email protected] To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-users
