On Mon, Oct 08, 2012 at 11:11:06AM +0200, Sietse Achterop wrote: > On 02-10-12 15:37, Sietse Achterop wrote: > > > I have 7 bluetooth devices (epucks, educational robots: http://www.e-puck.org/). > > They use the lmx9838 device for bluetooth and are seen as rfcomm-devices on linux. > > The lmx-device is used in transparent mode. > > This is on various linuxes, with kernels 2.6.32, 3.0.0 and 3.2, e.g. as in the latest ubuntu 12.04.1. > > > > The test program is a simple loop that continuously sends each epuck a small message, > > a string of say 6 characters. > > I use stdio's fprintf to send chars to the /dev/rfcomm devices. > > In pseudo code: > > open_devices(); > > while true do > > for i = 1 to 7 do > > fprintf(fp[i], "l,1,2\n"); > > od > > delay( 0.5 seconds); > > od > > > > This works perfectly if the delay statement is REMOVED. > > Then each 2 milliseconds a message is send to the next epuck. > > But if the delay is ADDED again it gets very UNRELIABLE. > > After 1 to 30 seconds a communication is failing and after a > > 20 second delay the connection of a epuck is dropped. > > After a longer time all connections are dropped. > > Dear list, > > to react on my on question, I just installed kernel 3.6.1, but the problem does > not go away:(. > It is random which of the epuck fails. > I would be grateful with some pointer. Could it be hardware in one of the BT devices? > I used a number of different dongles on the linux site. If it is a hardware problem, > it must be a structural problem in the hardware. > If it is no hardware problem, it has to be software on the linux site, because the lmx9838 is > used in transparent mode and the software is not much more than an echo and is software that > has been working for more than a year. > Am I using bluetooth in an unusual way? Get capture with hcidump like "hcidump -tX -i hciX". It will tell you why connection is closed. Also dmesg might give some warnings. Best regards Andrei Emeltchenko -- To unsubscribe from this list: send the line "unsubscribe linux-bluetooth" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
