Date: Mon, 27 Oct 1997 13:31:56 +0100 (MET) From: Christoph Kukulies <kuku@gilberto.physik.RWTH-Aachen.DE> To: freebsd-hackers@freefall.FreeBSD.org Subject: mmap/mlock problem Message-ID: <199710271231.NAA03303@gil.physik.rwth-aachen.de>
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I've written a driver for an industrial control card (portions of it coppered from /sys/i386/isa/spigot.c as far as the mmap stuff is concerned) With regard to the mapping into a user program it seems to work but the mapped memory region behaves differently in the user process. The ISA mapped memory is a dual ported RAM which is controlled by the on board CPU on one end and the user process on the other end. Writing something into the ISA memory should not result in reading the same back from it. But the fact of the matter is that I read back what I'v written into it and this seems to me as if the memory is cached. I tried a mlock call on the mmapped region but this seems to fail in the user process. Can anyone give me some assistance on getting further here? -- Chris Christoph P. U. Kukulies kuku@gil.physik.rwth-aachen.de
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