mmap doesn't work?

John Taves (jt@raf.com)
Thu, 25 Apr 1996 15:44:00 -0700

I can't seem to get mmap working. I am writing a device driver that
handles a pci card that receives image data. The driver works fine with
via the ioctl and read calls, but I want to avoid the copy from kernel
space to user space. I implemented the mmap call by copying code from the
mem device but it didn't work. No errors are reported but the pointer
that is returned from mmap(2) doesn't point to the data that the driver
put there. I tried mmap on the /dev/mem device (as root) and it didn't
give me the memory either.

Does the 1.3.59 kernel support this? I tried the 1.3.90 kernel and didn't
see any difference. If Linux doesn't support this when will it? Who
would like to make it work?

If it should work then I can supply a better description of what I did in
the hopes that someone can tell me where I am doing it wrong.

Thanks,

jt

jt@raf.com