--- Christine Ames <clgisotti@yahoo.com> wrote: > --- 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? > > > > __va() will work, but only with low memory addresses. > > See http://www.xml.com/ldd/chapter/book/ch13.html#t1 > > Best of luck, ;-) > > --Christine > Sorry, only four hours sleep last night. __va() is a kernel call, I think, which would prevent you from accessing it from user space. Being a kernel newbie, I'm waiting for the flames, but I'd prefer instruction. :-) --cla __________________________________________________ Do You Yahoo!? Yahoo! Shopping - Mother's Day is May 12th! http://shopping.yahoo.com -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
