Don, Try checking out mISDN from git://git.misdn.eu/mISDN.git and compiling that version. Not quite sure what is going on with git.misdn.org vs git.misdn.eu, but the .eu repo compiled fine on my debian box, whereas the .org repo failed with the same error you are seeing. Regards, Caleb From: openbsc-bounces(a)lists.osmocom.org [mailto:openbsc-bounces@lists.osmocom.org] On Behalf Of Don Fanning Sent: Wednesday, February 01, 2012 2019 To: openbsc(a)lists.gnumonks.org Subject: Issues compiling lcr on debian squeeze for OpenBSC/Asterisk stack Hello All, I've been working on trying to get OpenBSC to work with Asterisk following this as a guide: http://openbsc.osmocom.org/trac/wiki/OpenBSC_LCR http://www.misdn.org/index.php/Howto_for_Debian Basically I'm missing the mISDN_l1loop kernel module. When trying to compile from the mISDN git repository i'm getting the following error when trying to compile  (Ubuntu - 10.04 LTS ) ./configure configure: error: kernel build tree does not exist build:/lib/modules/2.6.32-33-generic/build / source:/lib/modules/2.6.32-33-generic/source (Debian - 6.06) passes configure when "make modules" is running make[3]: Entering directory `/usr/src/linux-headers-2.6.32-5-686'   CC [M]  /root/mISDN/standalone/drivers/isdn/mISDN/l1oip_core.o   CC [M]  /root/mISDN/standalone/drivers/isdn/mISDN/l1oip_codec.o   CC [M]  /root/mISDN/standalone/drivers/isdn/mISDN/core.o   CC [M]  /root/mISDN/standalone/drivers/isdn/mISDN/fsm.o   CC [M]  /root/mISDN/standalone/drivers/isdn/mISDN/socket.o   CC [M]  /root/mISDN/standalone/drivers/isdn/mISDN/clock.o   CC [M]  /root/mISDN/standalone/drivers/isdn/mISDN/hwchannel.o /root/mISDN/standalone/drivers/isdn/mISDN/hwchannel.c: In function âmISDN_freedchannelâ: /root/mISDN/standalone/drivers/isdn/mISDN/hwchannel.c:113: error: implicit declaration of function âflush_work_syncâ make[6]: *** [/root/mISDN/standalone/drivers/isdn/mISDN/hwchannel.o] Error 1 make[5]: *** [_module_/root/mISDN/standalone/drivers/isdn/mISDN] Error 2 make[4]: *** [sub-make] Error 2 make[3]: *** [all] Error 2 make[3]: Leaving directory `/usr/src/linux-headers-2.6.32-5-686' make[2]: *** [modules_] Error 2 make[2]: Leaving directory `/root/mISDN/standalone' make[1]: *** [modules] Error 2 make[1]: Leaving directory `/root/mISDN/standalone' make: *** [modules] Error 2 root@OpenBSC:~/mISDN# I should note that Centos 5.7 and Gentoo give the same errors as Ubuntu....  Any assistance is appreciated. Regards, -Don