Re: [PATCH 12/24] drm/i915: Delay allocation of stolen space for FBC

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Tue,  4 Sep 2012 21:03:04 +0100
Chris Wilson <chris@chris-wilson.co.uk> wrote:

> As we may wish to wrap regions preallocated by the BIOS, we need to do
> that before carving out contiguous chunks of stolen space for FBC.
> 
> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/i915_drv.h        |    1 +
>  drivers/gpu/drm/i915/i915_gem_stolen.c |  110 ++++++++++++++++----------------
>  drivers/gpu/drm/i915/intel_display.c   |    3 +
>  3 files changed, 59 insertions(+), 55 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 533361e..31d3a9f 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -1491,6 +1491,7 @@ int i915_gem_evict_everything(struct drm_device *dev);
>  
>  /* i915_gem_stolen.c */
>  int i915_gem_init_stolen(struct drm_device *dev);
> +int i915_gem_stolen_setup_compression(struct drm_device *dev);
>  void i915_gem_cleanup_stolen(struct drm_device *dev);
>  
>  /* i915_gem_tiling.c */
> diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
> index a528e4a..17119d7 100644
> --- a/drivers/gpu/drm/i915/i915_gem_stolen.c
> +++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
> @@ -86,21 +86,13 @@ static unsigned long i915_stolen_to_physical(struct drm_device *dev)
>  	return base;
>  }
>  
> -static void i915_warn_stolen(struct drm_device *dev)
> -{
> -	DRM_INFO("not enough stolen space for compressed buffer, disabling\n");
> -	DRM_INFO("hint: you may be able to increase stolen memory size in the BIOS to avoid this\n");
> -}
> -
> -static void i915_setup_compression(struct drm_device *dev, int size)
> +static int i915_setup_compression(struct drm_device *dev, int size)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  	struct drm_mm_node *compressed_fb, *uninitialized_var(compressed_llb);
> -	unsigned long cfb_base;
> -	unsigned long ll_base = 0;
>  
> -	/* Just in case the BIOS is doing something questionable. */
> -	intel_disable_fbc(dev);
> +	DRM_DEBUG_KMS("reserving %d bytes of contiguous stolen space for FBC\n",
> +		      size);
>  
>  	compressed_fb = drm_mm_search_free(&dev_priv->mm.stolen, size, 4096, 0);
>  	if (compressed_fb)
> @@ -108,11 +100,11 @@ static void i915_setup_compression(struct drm_device *dev, int size)
>  	if (!compressed_fb)
>  		goto err;
>  
> -	cfb_base = dev_priv->mm.stolen_base + compressed_fb->start;
> -	if (!cfb_base)
> -		goto err_fb;
> -
> -	if (!(IS_GM45(dev) || HAS_PCH_SPLIT(dev))) {
> +	if (HAS_PCH_SPLIT(dev))
> +		I915_WRITE(ILK_DPFC_CB_BASE, compressed_fb->start);
> +	else if (IS_GM45(dev)) {
> +		I915_WRITE(DPFC_CB_BASE, compressed_fb->start);
> +	} else {
>  		compressed_llb = drm_mm_search_free(&dev_priv->mm.stolen,
>  						    4096, 4096, 0);
>  		if (compressed_llb)
> @@ -121,56 +113,78 @@ static void i915_setup_compression(struct drm_device *dev, int size)
>  		if (!compressed_llb)
>  			goto err_fb;
>  
> -		ll_base = dev_priv->mm.stolen_base + compressed_llb->start;
> -		if (!ll_base)
> -			goto err_llb;
> -	}
> +		dev_priv->compressed_llb = compressed_llb;
>  
> -	dev_priv->cfb_size = size;
> +		I915_WRITE(FBC_CFB_BASE,
> +			   dev_priv->mm.stolen_base + compressed_fb->start);
> +		I915_WRITE(FBC_LL_BASE,
> +			   dev_priv->mm.stolen_base + compressed_llb->start);
> +	}
>  
>  	dev_priv->compressed_fb = compressed_fb;
> -	if (HAS_PCH_SPLIT(dev))
> -		I915_WRITE(ILK_DPFC_CB_BASE, compressed_fb->start);
> -	else if (IS_GM45(dev)) {
> -		I915_WRITE(DPFC_CB_BASE, compressed_fb->start);
> -	} else {
> -		I915_WRITE(FBC_CFB_BASE, cfb_base);
> -		I915_WRITE(FBC_LL_BASE, ll_base);
> -		dev_priv->compressed_llb = compressed_llb;
> -	}
> +	dev_priv->cfb_size = size;
>  
> -	DRM_DEBUG_KMS("FBC base 0x%08lx, ll base 0x%08lx, size %dM\n",
> -		      (long)cfb_base, (long)ll_base, size >> 20);
> -	return;
> +	return size;
>  
> -err_llb:
> -	drm_mm_put_block(compressed_llb);
>  err_fb:
>  	drm_mm_put_block(compressed_fb);
>  err:
>  	dev_priv->no_fbc_reason = FBC_STOLEN_TOO_SMALL;
> -	i915_warn_stolen(dev);
> +	DRM_INFO("not enough stolen space for compressed buffer (need %d bytes), disabling\n", size);
> +	DRM_INFO("hint: you may be able to increase stolen memory size in the BIOS to avoid this\n");
> +	return 0;
> +}
> +
> +int i915_gem_stolen_setup_compression(struct drm_device *dev)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	struct drm_mm_node *node;
> +	unsigned long hole_start, hole_end, size;
> +
> +	if (dev_priv->mm.stolen_base == 0)
> +		return 0;
> +
> +	if (dev_priv->cfb_size)
> +		return dev_priv->cfb_size;
> +
> +	/* Try to set up FBC with a reasonable compressed buffer size */
> +	size = 0;
> +	drm_mm_for_each_hole(node, &dev_priv->mm.stolen, hole_start, hole_end) {
> +		unsigned long hole_size = hole_end - hole_start;
> +		if (hole_size > size)
> +			size = hole_size;
> +	}
> +
> +	/* Try to get a 32M buffer... */
> +	if (size > (36*1024*1024))
> +		size = 32*1024*1024;
> +	else /* fall back to 3/4 of the stolen space */
> +		size = size * 3 / 4;
> +
> +	return i915_setup_compression(dev, size);
>  }
>  
>  static void i915_cleanup_compression(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
>  
> -	drm_mm_put_block(dev_priv->compressed_fb);
> +	if (dev_priv->compressed_fb)
> +		drm_mm_put_block(dev_priv->compressed_fb);
> +
>  	if (dev_priv->compressed_llb)
>  		drm_mm_put_block(dev_priv->compressed_llb);
> +
> +	dev_priv->cfb_size = 0;
>  }
>  
>  void i915_gem_cleanup_stolen(struct drm_device *dev)
>  {
> -	if (I915_HAS_FBC(dev) && i915_powersave)
> -		i915_cleanup_compression(dev);
> +	i915_cleanup_compression(dev);
>  }
>  
>  int i915_gem_init_stolen(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = dev->dev_private;
> -	unsigned long prealloc_size = dev_priv->mm.gtt->stolen_size;
>  
>  	dev_priv->mm.stolen_base = i915_stolen_to_physical(dev);
>  	if (dev_priv->mm.stolen_base == 0)
> @@ -180,21 +194,7 @@ int i915_gem_init_stolen(struct drm_device *dev)
>  		      dev_priv->mm.gtt->stolen_size, dev_priv->mm.stolen_base);
>  
>  	/* Basic memrange allocator for stolen space */
> -	drm_mm_init(&dev_priv->mm.stolen, 0, prealloc_size);
> -
> -	/* Try to set up FBC with a reasonable compressed buffer size */
> -	if (I915_HAS_FBC(dev) && i915_powersave) {
> -		int cfb_size;
> -
> -		/* Leave 1M for line length buffer & misc. */
> -
> -		/* Try to get a 32M buffer... */
> -		if (prealloc_size > (36*1024*1024))
> -			cfb_size = 32*1024*1024;
> -		else /* fall back to 7/8 of the stolen space */
> -			cfb_size = prealloc_size * 7 / 8;
> -		i915_setup_compression(dev, cfb_size);
> -	}
> +	drm_mm_init(&dev_priv->mm.stolen, 0, dev_priv->mm.gtt->stolen_size);
>  
>  	return 0;
>  }
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 778cbb8..221d035 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -7231,6 +7231,9 @@ void intel_modeset_init(struct drm_device *dev)
>  	/* Just disable it once at startup */
>  	i915_disable_vga(dev);
>  	intel_setup_outputs(dev);
> +
> +	/* Just in case the BIOS is doing something questionable. */
> +	intel_disable_fbc(dev);
>  }
>  
>  void intel_modeset_gem_init(struct drm_device *dev)

Assuming you actually call this function in a later patch:

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>

-- 
Jesse Barnes, Intel Open Source Technology Center