Re: [PATCH v2] drm/atomic: Initialize variables in drm_atomic_helper_async_check() to make gcc happy

[Boris Brezillon <boris.brezillon@bootlin.com>]

On Tue, 24 Jul 2018 15:33:00 +0200
Boris Brezillon <boris.brezillon@bootlin.com> wrote:

> drm_atomic_helper_async_check() declares the plane, old_plane_state and
> new_plane_state variables to iterate over all planes of the atomic
> state and make sure only one plane is enabled.
> 
> Unfortunately gcc is not smart enough to figure out that the check on
> n_planes is enough to guarantee that plane, new_plane_state and
> old_plane_state are initialized.
> 
> Explicitly initialize those variables to NULL to make gcc happy.
> 
> Fixes: fef9df8b5945 ("drm/atomic: initial support for asynchronous plane update")
> Cc: <stable@vger.kernel.org>
> Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
> Reviewed-by: Sean Paul <seanpaul@chromium.org>

Applied to drm-misc-fixes.

> ---
> Changes in v2:
> - Cc stable
> - Add Sean's R-b
> - Fix a typo in the commit message
> ---
>  drivers/gpu/drm/drm_atomic_helper.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index f7ccfebd3ca8..80be74df7ba6 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -1538,8 +1538,9 @@ int drm_atomic_helper_async_check(struct drm_device *dev,
>  {
>  	struct drm_crtc *crtc;
>  	struct drm_crtc_state *crtc_state;
> -	struct drm_plane *plane;
> -	struct drm_plane_state *old_plane_state, *new_plane_state;
> +	struct drm_plane *plane = NULL;
> +	struct drm_plane_state *old_plane_state = NULL;
> +	struct drm_plane_state *new_plane_state = NULL;
>  	const struct drm_plane_helper_funcs *funcs;
>  	int i, n_planes = 0;
>