On Tue, 20 Oct 2020 at 18:31, Christian König christian.koenig@amd.com wrote:
Yes, please! That approach looks even better than what I had in mind.
A few comments below:
Am 20.10.20 um 06:16 schrieb Dave Airlie:
From: Dave Airlie airlied@redhat.com
[SNIP]
/* don't go from system->vram in one hop,report this back to the caller tell itwhere to bounce this buffer through. */if ((old_mem->mem_type == TTM_PL_SYSTEM &&new_mem->mem_type == TTM_PL_VRAM) ||(old_mem->mem_type == TTM_PL_VRAM &&new_mem->mem_type == TTM_PL_SYSTEM)) {new_mem->mem_type = TTM_PL_TT;Not sure if that is such a good idea, new_mem can be some allocated memory in the VRAM domain at this moment.
Maybe instead give the callback a separate bounce argument instead.
I've changed this in the latest posting to take a ttm_place that the driver fills out if it needs a hop.
/* find space in the bounce domain */ret = ttm_bo_mem_space(bo, &bounce_placement, mem, ctx);if (ret)return ret;/* move to the bounce domain */ret = ttm_bo_handle_move_mem(bo, mem, false, ctx);Is this a recursion? I don't think it is, but I thought I better double check.
No it should never recurse because the driver should only return -EMULTIHOP once, even if a theoretical driver was to need > 1 hops it should work until it returns something other than -EMULTIHOP. Of course a broken driver could cause bad things, but that is always true.
Dave.