Richard Kirk wrote: Hi, Pascal de Bruijn has reported some problems with USB timeouts on Linux with the ColorMunki. His symptoms were that it would work the first time after plugging in, but not thereafter. My suspicion was that is some sort of bug in the Linux driver for a particular USB hub on his motherboard, but without help from one of the Linux USB driver writers, it's hard to be sure what the cause is. > It works when I 'su root'. It does not work when I run it with 'sudo' That's strange. Usually such problems are to do with permissions to open the device - ie. setting up a suitable udev file. > Here's the errors with 'sudo'... > > richard@gallardo$ sudo ./Argyll_V1.6.3/bin/spotread -D9 > > I won't attach all of the dump as it is enormous and I don't want to plague > everyone with > it. But here is the bit starting just before my attempt at a measurement... > > avg_multi: overall avg = 1857.421875, minavg = 1857.421875, maxavg = > 1857.421875, variance > 0.000000, THR 0.050000 (darkth 5000.000000) > Saving adaptive black calib to similar modes > Done adaptive interpolated black calibration > urb_reaper: poll returned -1 and events 0 0 > urb_reaper: shutdown or too many failure > urb_reaper: cleared requests > urb_reaper: thread done I think the driver has effectively failed at this point, because poll() has returned -1 so it thinks the driver is shutting down. Without the reaper thread, no USB transfers will complete. What happened before this ? (ie., since you have ommitted the trace, it's not clear whether USB transfers were working before this, or what led up to poll failing). Graeme Gill.