Le lundi 28 mai 2012 à 00:38 -0300, Bruno Jesus a écrit : > > I have worked in a project where we needed the max possible amount of > readers to build a SAM server. We ended up with 104 readers + 20 hubs > (looks like the usb device limit is 127). The main problem was that > the motherboard was not able to provide enough power for all the > readers so we elected 4 usb hubs that were powered externally. Each of > these main hubs are connected to a different motherboard usb port. On > each main hub we connected 4 other hubs. So we ended up with 16 > secondary hubs with 6 or 7 readers each. Some cheap brands of hubs > bought from dealextreme could not handle that amount of readers, > specially some fake 7 port hubs which are in fact 2 hubs of 4 ports > interconnected. You should try other brands of hubs if you have > problems with power and disconnection. You can always look at dmesg to > see if the readers are getting recognized/disconnected.
Thank you very much for this information.
We are not using cheap USB hubs, but so-called "industrial" hubs powered
externally. Each hub is connecting directly on the motherboard (7 ports)
or on a PCI card (4 ports). Casing is made of steel to reduce the risk
of fire, which is my main concern when running a farm.
Looking at dmseg, I can read:
[ 52.832147] usb 2-1.1.4: usbfs: USBDEVFS_CONTROL failed cmd pcscd rqt
161 rq 3 len 1024 ret -110
Do you what it means?
Kind regards,
--
Jean-Michel Pouré - Gooze - http://www.gooze.eu
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