The HyperNews Linux KHG Discussion Pages

## Problem with user-space device driver. Help!

  Forum: User-space device drivers
  Date: Wed, 15 Oct 1997 12:01:15 GMT
  From: Peter Knego <peter.knego@xenya.si>

Hi everybody! I am writing a user-space device driver for a frame grabber, which is esentially a memory-mapped device. It uses several I/O ports plus a 32k block of memory at D0000h. (or E0000h) It works nice under DOS with original libs and there seems to be no conflict with other hardware. When I start it under Linux and use my user-space driver (library) to do some grabbing (and drawing as this equipment has an external monitor for the picture grabbed) I see garbage . If I start drawing something (writing to D0000h) the system usualy locks up. Looks like someone else is also using this block of memory. I am using mmap() to write and read to this memory block. I thought that memory between A0000h-10000h is not used by kernel or user processes. Is there a way to protect (reserve) this block of memory (32k at D0000)? Thank for your help. Peter Knego, Xenya d.o.o. peter.knego@xenya.si