[PATCH] drm/crtc-helper: Add caveat to disable_unused_functions doc

[Daniel Vetter]

On Wed, Jan 13, 2016 at 03:31:16PM +0100, Daniel Vetter wrote:
> This shouldn't be used by atomic drivers any more, it confuses the
> state tracking.
> 
> Cc: Maxime Ripard <maxime.ripard at free-electrons.com>
> Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Acked-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>

Applied this one to drm-misc.
-Daniel

> ---
>  drivers/gpu/drm/drm_crtc_helper.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
> index a02a7f9a6a9d..a278fbbe23e0 100644
> --- a/drivers/gpu/drm/drm_crtc_helper.c
> +++ b/drivers/gpu/drm/drm_crtc_helper.c
> @@ -220,6 +220,15 @@ static void __drm_helper_disable_unused_functions(struct drm_device *dev)
>   * disconnected connectors. Then it will disable all unused encoders and CRTCs
>   * either by calling their disable callback if available or by calling their
>   * dpms callback with DRM_MODE_DPMS_OFF.
> + *
> + * NOTE:
> + *
> + * This function is part of the legacy modeset helper library and will cause
> + * major confusion with atomic drivers. This is because atomic helpers guarantee
> + * to never call ->disable() hooks on a disabled function, or ->enable() hooks
> + * on an enabled functions. drm_helper_disable_unused_functions() on the other
> + * hand throws such guarantees into the wind and calls disable hooks
> + * unconditionally on unused functions.
>   */
>  void drm_helper_disable_unused_functions(struct drm_device *dev)
>  {
> -- 
> 2.7.0.rc3
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch