From a3a402840662a7449b1ca0baa58eddf36ef23158 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Mon, 6 Jul 2020 23:43:08 +0100 Subject: [PATCH] drm/i915: Update dma-attributes for our sg DMA Looking through the attributes for DMA mappings, it appears that by default dma_map_sg will try and create a kernel accessible map of the page. We never access this, as we either have a struct page already or an iomap, so we can request that the dma mapper does not create one. Without a kernel map in place, one presumes the rest of the memory control attributes do not apply. We also explicitly control the caches around the mappings, so we can ask it not to bother synchronising itself. Signed-off-by: Chris Wilson Cc: Matthew Auld Reviewed-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20200706224308.22636-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_gem_gtt.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index cb43381b0d37b..c5ee1567f3d1b 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -31,6 +31,8 @@ int i915_gem_gtt_prepare_pages(struct drm_i915_gem_object *obj, if (dma_map_sg_attrs(&obj->base.dev->pdev->dev, pages->sgl, pages->nents, PCI_DMA_BIDIRECTIONAL, + DMA_ATTR_SKIP_CPU_SYNC | + DMA_ATTR_NO_KERNEL_MAPPING | DMA_ATTR_NO_WARN)) return 0; -- 2.30.2