It doesn't seem to be possible to use image2d_t as a kernel argument. I get this error whenever I added a texture to the kernel arguments:
error: kernel must return void; pointer argument must point to addrSpace global, local, or constant
I tried adding a local, global, constant modifer, but it makes no difference (is that a legal thing to do anyway ? I was assuming not)
Additionally the modifiers read_only (or __read_only) cause compile errors.
This is under Windows XP 32-bit and Beta-3.