In my driver module, I am using mdelay() call to wait 400 to 1000, after sending command to hardware and before reading results. Is this proper way to wait ? My intend is to wait 400 milliseconds or 1000 milliseconds. My driver is used in two env (1) boot from floopy and NFS mount the root (where all the driver modules and application programs are. (2) Boot from CDROM and mount CDROM as the root. My driver is loaded after Linux is fully up, by shell script. It works fine in case 1 and always hangs when mdelay call is executed in case 2. I have moved location of mdelay, and it always hangs when mdelay call is executed. Any insight why mdelay would hang ? __________________________________ Do you Yahoo!? New Yahoo! Photos - easier uploading and sharing. http://photos.yahoo.com/ -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/