Re: [PATCH 11/11] drm/i915: Don't modeset with old mode when set_crtc fails

[Daniel Vetter <daniel@ffwll.ch>]

On Fri, Apr 10, 2015 at 11:38:40AM +0300, Ander Conselvan de Oliveira wrote:
> The modeset code is now properly divided in two phases, so that it only
> changes hardware state if it succeeds, so there's no ill-effect that
> needs to be undone on failure anymore.
> ---
>  drivers/gpu/drm/i915/intel_display.c | 48 ------------------------------------
>  1 file changed, 48 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 06f3b83..84efd7a 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -12136,33 +12136,9 @@ intel_modeset_stage_output_state(struct drm_device *dev,
>  	return 0;
>  }
>  
> -static void disable_crtc_nofb(struct intel_crtc *crtc)
> -{
> -	struct drm_device *dev = crtc->base.dev;
> -	struct intel_encoder *encoder;
> -	struct intel_connector *connector;
> -
> -	DRM_DEBUG_KMS("Trying to restore without FB -> disabling pipe %c\n",
> -		      pipe_name(crtc->pipe));
> -
> -	for_each_intel_connector(dev, connector) {
> -		if (connector->new_encoder &&
> -		    connector->new_encoder->new_crtc == crtc)
> -			connector->new_encoder = NULL;
> -	}
> -
> -	for_each_intel_encoder(dev, encoder) {
> -		if (encoder->new_crtc == crtc)
> -			encoder->new_crtc = NULL;
> -	}
> -
> -	crtc->new_enabled = false;
> -}
> -
>  static int intel_crtc_set_config(struct drm_mode_set *set)
>  {
>  	struct drm_device *dev;
> -	struct drm_mode_set save_set;
>  	struct drm_atomic_state *state = NULL;
>  	struct intel_set_config *config;
>  	struct intel_crtc_state *pipe_config;
> @@ -12195,12 +12171,6 @@ static int intel_crtc_set_config(struct drm_mode_set *set)
>  	if (ret)
>  		goto out_config;
>  
> -	save_set.crtc = set->crtc;
> -	save_set.mode = &set->crtc->mode;
> -	save_set.x = set->crtc->x;
> -	save_set.y = set->crtc->y;
> -	save_set.fb = set->crtc->primary->fb;
> -
>  	state = drm_atomic_state_alloc(dev);
>  	if (!state) {
>  		ret = -ENOMEM;
> @@ -12280,24 +12250,6 @@ static int intel_crtc_set_config(struct drm_mode_set *set)
>  			      set->crtc->base.id, ret);
>  fail:
>  		intel_set_config_restore_state(dev, config);
> -
> -		drm_atomic_state_clear(state);
> -
> -		/*
> -		 * HACK: if the pipe was on, but we didn't have a framebuffer,
> -		 * force the pipe off to avoid oopsing in the modeset code
> -		 * due to fb==NULL. This should only happen during boot since
> -		 * we don't yet reconstruct the FB from the hardware state.
> -		 */
> -		if (to_intel_crtc(save_set.crtc)->new_enabled && !save_set.fb)
> -			disable_crtc_nofb(to_intel_crtc(save_set.crtc));
> -
> -		/* Try to restore the config */
> -		if (config->mode_changed &&
> -		    intel_set_mode(save_set.crtc, save_set.mode,
> -				   save_set.x, save_set.y, save_set.fb,
> -				   state))
> -			DRM_ERROR("failed to restore config after modeset failure\n");

Hm removing this reminds me that we still have troubles with always
assuming that there is a primary fb around. Getting rid of all the fb
pointers in our modeset code looks like a sizeable task too.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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