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Commit be7d9f05 authored by Boris Brezillon's avatar Boris Brezillon Committed by Rob Herring
Browse files

drm/gem_shmem: Use a writecombine mapping for ->vaddr 



Right now, the BO is mapped as a cached region when ->vmap() is called
and the underlying object is not a dmabuf.
Doing that makes cache management a bit more complicated (you'd need
to call dma_map/unmap_sg() on the ->sgt field everytime the BO is about
to be passed to the GPU/CPU), so let's map the BO with writecombine
attributes instead (as done in most drivers).

Fixes: 2194a63a ("drm: Add library for shmem backed GEM objects")
Signed-off-by: default avatarBoris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: default avatarEric Anholt <eric@anholt.net>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190529065121.13485-1-boris.brezillon@collabora.com
parent 652b8b08

drivers/gpu/drm/drm_gem_shmem_helper.c

+2 −1
Original line number Diff line number Diff line
@@ -255,7 +255,8 @@ static void *drm_gem_shmem_vmap_locked(struct drm_gem_shmem_object *shmem) 
	if (obj->import_attach)

		shmem->vaddr = dma_buf_vmap(obj->import_attach->dmabuf);

	else

		shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT, VM_MAP, PAGE_KERNEL);

		shmem->vaddr = vmap(shmem->pages, obj->size >> PAGE_SHIFT,

				    VM_MAP, pgprot_writecombine(PAGE_KERNEL));



	if (!shmem->vaddr) {

		DRM_DEBUG_KMS("Failed to vmap pages\n");