From be7d9f05c53e6fc88525f8e55cf2dae937761799 Mon Sep 17 00:00:00 2001 From: Boris Brezillon Date: Wed, 29 May 2019 08:51:21 +0200 Subject: [PATCH] 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: 2194a63a818d ("drm: Add library for shmem backed GEM objects") Signed-off-by: Boris Brezillon Reviewed-by: Daniel Vetter Reviewed-by: Eric Anholt Signed-off-by: Rob Herring Link: https://patchwork.freedesktop.org/patch/msgid/20190529065121.13485-1-boris.brezillon@collabora.com --- drivers/gpu/drm/drm_gem_shmem_helper.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index 1ee208c..472ea5d 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -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"); -- 2.7.4