Renaud Gu�rin wrote:
>
> Hello,
>
> I'm in a situation where I need to plug 24 high bandwidths USB devices into
> the same machine (they're DSL modems actually).
>
> I'm using 6 hubs, 2 of them plugged directly on the PC, and the fours others
> on the first hubs. Every hub has in turn 4 devices plugged in.
>
> The trouble is that all the bandwidth is soon taken up, in ISO mode I get "usb
> check bandwidth would have failed" messages, and in bulk mode, thousands of
> "ENXIO" messages.
>
> I determined that I can safely plug up to 8 modems on this setup, and after
> that the USB bus collapses.
>
> So I think I'm gonna use 2 additional PCI USB host controllers, if that means
> each of them has its own bus and bandwidth.
>
> Can anyone confirm that I'll have indeed 3x12Mbps, and can
> usb-uhci/usb-ohci/uhci handle this setup ?
>
> Thanks a lot...
I have a system that I just built that has 6 pci HC's.
If your devices and hubs, are USB-1.1,
the hubs are going to kill you.
That looks like whats happening.
The pci HC's I'm using have the NEC upd72100 controller on them.
Each HC has 2 ohci controllers, one controller has 2 ports,
the other has 3 ports.
Each HC has 1 ehci controller that has 5 ports.
The numbers that I get are:
1 device on 1 port, 900k bytes/sec.
2 devices on 1 port, 450k bytes/sec.
"cat /proc/bus/usb/devices|grep Bus"
Will show you what you have.
Here are some numbers I just ran: 2.4.21-pre5
USB-2.0, 4 port hub, connected to ehci port:
devices are USB-1.1 flash.
devices xfer
4 285kb
3 381kb
2 571kb
1 841kb
I hope this help.
gary,
--
Gary A. Gorgen | "From ideas to PRODUCTS"
| Tunxis Design Inc.
[EMAIL PROTECTED] | 10470 Pineville Ave. Cupertino, Ca. 95014
| Phone: (408) 973-1542
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