[Linux-ia64] mmap crashes system after mapping PCI device into user space and reading and writing.

["Mike Fox" <mfox@annapmicro.com>]

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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.

 

 


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