From: Xianting Tian <xianting.tian@xxxxxxxxxxxxxxxxx> commit 0a727b459ee39bd4c5ced19d6024258ac87b6b2e upstream. 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> Fixes: 072f1f9168ed ("drm/msm: add support for "stolen" mem") Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220112123334.749776-1-xianting.tian@xxxxxxxxxxxxxxxxx Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/gpu/drm/msm/msm_drv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -350,7 +350,7 @@ static int msm_init_vram(struct drm_devi 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.