For example, memory-region in .dts as below, reg = <0x0 0x50000000 0x0 0x20000000> We can get below values, struct resource r; r.start = 0x50000000; r.end = 0x6fffffff; So the size should be: size = r.end - r.start + 1 = 0x20000000 Signed-off-by: Xianting Tian <xianting.tian@xxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/msm/msm_drv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c index 892c04365..f04a2337d 100644 --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -466,7 +466,7 @@ static int msm_init_vram(struct drm_device *dev) of_node_put(node); if (ret) return ret; - size = r.end - r.start; + size = r.end - r.start + 1; DRM_INFO("using VRAM carveout: %lx@%pa\n", size, &r.start); /* if we have no IOMMU, then we need to use carveout allocator. -- 2.17.1