Messages in this thread | | | Subject | Re: help on driver's nopage mmap method | From | Steven Rostedt <> | Date | Wed, 22 Dec 2004 07:51:11 -0500 |
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On Tue, 2004-12-21 at 21:23 -0800, John Wang wrote: > Hi, I have been struggling for a couple of days about > a problem of using nopage method to mmap memory from > driver to user application. > > What I try to do is very simple - just to get the > simplest case to work, but I always get some junk in > user app (to be more specific, always 0xFF in the mmap > the memory area). I don't know what is wrong here - it > appears perfectly normal (compared to the examples in > the book Linux Device Driver). The kernel is 2.4.2 > running on Intel x86 platform. > > The program is very simple so I attached here (header > includes are ignored here to shorten the length). > Please CC me directly if anyone has answer since I am > not subscribed to the mailing list. Thanks in advance.
I just tried your program on both 2.4.20 and 2.6.9 and it works fine. Kernel 2.4.2 is very old, you might want to try a different kernel.
-- Steve
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