Hi, I am running kernel version 2.4.19 and I am getting a system crash when I mmap my PCI device into user space and access it. It seems to be the same issue that was posted earlier in the following post, which had no response: Has anyone tried using mmap to remap PCI device memory into user space? I have seen the following problem: If I do the mmap, it returns successfully, and I can indeed access the device memory. Unfortunately, the system will hang within about a minute after doing so. I do not get an oops, or crash of any kind, simply no further response form the machine. If I just do the mmap and then munmap the system will not hang. But if I do one access to the mmapped address, the system will hang. I am using the remap_page_range call in my mmap routine, and this same code works on x86 and Alpha platforms. I found it odd that it takes a while for the system to hang after the access, is their something special I have to do for this to work on IA64? I am running 2.4.1 with the 1/31 patch, although this problem occurs on all previous kernels I have tried. Thanks in advance for any insight anyone might have. Thanks for any help you can give. I'm new to Linux and IA64 and I am in a rush to port a PCI driver and API. Thanks, Mike Fox.