Re: [PATCH 1/2] drm/i915: Explicitly cleanup initial_plane_config

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Nov 12, 2019 at 02:36:42PM +0000, Chris Wilson wrote:
> I am about to stuff more objects into the plane_config and would like to
> have it clean up after itself. Move the current framebuffer release into
> a common function so it can be extended with the new object with
> relative ease.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 20 +++++++++++++++-----
>  1 file changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 5f3340554149..f571c6575c62 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -3241,8 +3241,6 @@ intel_find_initial_plane_obj(struct intel_crtc *intel_crtc,
>  		goto valid_fb;
>  	}
>  
> -	kfree(plane_config->fb);
> -
>  	/*
>  	 * Failed to alloc the obj, check to see if we should share
>  	 * an fb with another CRTC instead
> @@ -3262,7 +3260,6 @@ intel_find_initial_plane_obj(struct intel_crtc *intel_crtc,
>  
>  		if (intel_plane_ggtt_offset(state) == plane_config->base) {
>  			fb = state->hw.fb;
> -			drm_framebuffer_get(fb);
>  			goto valid_fb;
>  		}
>  	}
> @@ -3295,7 +3292,6 @@ intel_find_initial_plane_obj(struct intel_crtc *intel_crtc,
>  			  intel_crtc->pipe, PTR_ERR(intel_state->vma));
>  
>  		intel_state->vma = NULL;
> -		drm_framebuffer_put(fb);
>  		return;
>  	}
>  
> @@ -3317,7 +3313,6 @@ intel_find_initial_plane_obj(struct intel_crtc *intel_crtc,
>  	if (plane_config->tiling)
>  		dev_priv->preserve_bios_swizzle = true;
>  
> -	plane_state->fb = fb;

This stuff looks wrong. We still want the plane state to point at the
fb.

Ideally I'd like to nuke the plane_config thing entirely and just read
everything directly into the plane_states(s), but that's probably a
bunch of actual work so not going to happen soon.

>  	plane_state->crtc = &intel_crtc->base;
>  	intel_plane_copy_uapi_to_hw_state(intel_state, intel_state);
>  
> @@ -16952,6 +16947,19 @@ static void intel_mode_config_init(struct drm_i915_private *i915)
>  	}
>  }
>  
> +static void plane_config_fini(struct intel_initial_plane_config *plane_config)
> +{
> +	if (plane_config->fb) {
> +		struct drm_framebuffer *fb = &plane_config->fb->base;
> +
> +		/* We may only have the stub and not a full framebuffer */
> +		if (drm_framebuffer_read_refcount(fb))
> +			drm_framebuffer_put(fb);
> +		else
> +			kfree(fb);
> +	}
> +}
> +
>  int intel_modeset_init(struct drm_i915_private *i915)
>  {
>  	struct drm_device *dev = &i915->drm;
> @@ -17036,6 +17044,8 @@ int intel_modeset_init(struct drm_i915_private *i915)
>  		 * just get the first one.
>  		 */
>  		intel_find_initial_plane_obj(crtc, &plane_config);
> +
> +		plane_config_fini(&plane_config);
>  	}
>  
>  	/*
> -- 
> 2.24.0

-- 
Ville Syrjälä
Intel
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