On Tue, Jun 07, 2011 at 08:59:28PM +0100, Alan Cox wrote:
I'm not sure I understand you correctly. I have no address space on the card side since my 'card' just uses main memory. The memory I need must be a physically contiguous portion of sdram. I'm afraid shmem backing memory is not of much use for me.
I hadn't realised you had that underlying limit. If you are limited to a specific chunk of SDRAM and it must be physically linear rather than any of memory then indeed it's not.
I'd been tweaking GEM so you can borrow the abstraction and handles but back them with your own allocator but in my case it makes sense because I can use either main memory or a chunk of linear preallocated memory reserved by the firmware so I wanted the commonality and single set of handles for GEM, IOCTL_MODE_CREATE_DUMB etc.
Your patch looks like it would do the trick. I'll see what I can do.
Sascha