On Thu, Jun 14, 2001 at 10:53:15AM +0200, Jean-Jacques Tchouto wrote:
> Hi,
>
> I have a host with the folowing component:
> - RedHat 7.1 distrubution
> - Intel Pentium III 700 MHz
> - kernel 2.4.5 without patch
> - USB Controller: Intel Corporation 82371AB PIIX4 USB (rev1)
> UHCI
> - 4 TerraCam usb and 4 usb philips 680 Vesta Pro camera.
>
> The problem:
> I run video application which use the video devices.
> When a run for example two appliactions which uses
> two differents video devices (e.g. app1 uses /dev/video1
> and app2 uses /dev/video2) a problem accur, and I only
> get black picture. Attach to this mail you will found
> the kernel log and the lspcilog files.
>
> I need an advice for this problem.
To me it looks like you are needing too much USB bandwidth with more than
one camera. Without the kernel option "bandwidth checking", there's no check
if that can appear, and the transfers will fail.
Remember, USB is a shared medium, and even two USB-ports on a mainboard
usually are connected to one USB controller with 12Mit/s total for all
ports. Only newer VIA chipsets have two UHCI controllers, thus doubling the
bandwidth.
--
Georg Acher, [EMAIL PROTECTED]
http://www.in.tum.de/~acher/
"Oh no, not again !" The bowl of petunias
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