Usman S. Ansari wrote: >When user process calls mmap system call, this address is setup by the kernel along with size, >this I figure is setup in some suitable place in the user process virtual space. > >Usman > But since I am the device driver writer, I am responsible for this...correct? > > >--- David Stroupe <dstroupe@keyed-upsoftware.com> wrote: > >>I am developing a framegrabber driver. I need to map memory for the >>grabber to DMA the images into. I have it working currently where the >>grab happens into kernel memory and then I copy_to_user to get the >>buffer into user space. I think I can eliminate this step by using >>remap_page_range which would allow me to access the grabbed images >>directly from user space. The argument to remap_page_range that I don't >>understand is the first argument...the virtual address. I know how big >>the buffer is, I know the physical address of the buffer allocated in >>the kernel, I have to set the protection such that the pages are not >>swapped...how do I get a virtual address to pass to the driver so that >>this mapping can take place? >> Best regards, David Stroupe Keyed-Up Software 5307 Faireast Court Arlington, Texas 76018-1683 817/557-4903 voice 817/472-0408 fax -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
