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drm/i915: Try harder to get FBC 

The GEN FBC unit provides the ability to set a low pass on frames it
attempts to compress. If a frame is less than a certain amount
compressibility (2:1, 4:1) it will not bother. This allows the driver to
reduce the size it requests out of stolen memory.

Unluckily, a few months ago, Ville actually began using this feature for
framebuffers that are 16bpp (not sure why not 8bpp). In those cases, we
are already using this mechanism for a different purpose, and so we can
only achieve one further level of compression (2:1 -> 4:1)

FBC GEN1, ie. pre-G45 is ignored.

The cleverness of the patch is Art's. The bugs are mine.

v2: Update message and including missing threshold case 3 (Spotted by Arthur).

Cc: Art Runyan <arthur.j.runyan@intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
hifive-unleashed-5.1
Ben Widawsky 2014-06-30 10:41:24 -07:00 committed by Jani Nikula
parent edc0fdbbf6
commit 5e59f7175f
3 changed files with 70 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
drivers/gpu/drm/i915/i915_drv.h
View File

@ -600,6 +600,7 @@ struct intel_context {
struct i915_fbc {
unsigned long size;
unsigned threshold;
unsigned int fb_id;
enum plane plane;
int y;
@ -2487,7 +2488,7 @@ static inline void i915_gem_chipset_flush(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, int size);
int i915_gem_stolen_setup_compression(struct drm_device *dev, int size, int fb_cpp);
void i915_gem_stolen_cleanup_compression(struct drm_device *dev);
void i915_gem_cleanup_stolen(struct drm_device *dev);
struct drm_i915_gem_object *

56
drivers/gpu/drm/i915/i915_gem_stolen.c
View File

@ -105,35 +105,61 @@ static unsigned long i915_stolen_to_physical(struct drm_device *dev)
static int find_compression_threshold(struct drm_device *dev,
struct drm_mm_node *node,
int size)
int size,
int fb_cpp)
{
struct drm_i915_private *dev_priv = dev->dev_private;
const int compression_threshold = 1;
int compression_threshold = 1;
int ret;
/* Try to over-allocate to reduce reallocations and fragmentation */
/* HACK: This code depends on what we will do in *_enable_fbc. If that
* code changes, this code needs to change as well.
*
* The enable_fbc code will attempt to use one of our 2 compression
* thresholds, therefore, in that case, we only have 1 resort.
*/
/* Try to over-allocate to reduce reallocations and fragmentation. */
ret = drm_mm_insert_node(&dev_priv->mm.stolen, node,
size <<= 1, 4096, DRM_MM_SEARCH_DEFAULT);
if (ret)
ret = drm_mm_insert_node(&dev_priv->mm.stolen, node,
size >>= 1, 4096,
DRM_MM_SEARCH_DEFAULT);
if (ret)
return 0;
else
if (ret == 0)
return compression_threshold;
again:
/* HW's ability to limit the CFB is 1:4 */
if (compression_threshold > 4 ||
(fb_cpp == 2 && compression_threshold == 2))
return 0;
ret = drm_mm_insert_node(&dev_priv->mm.stolen, node,
size >>= 1, 4096,
DRM_MM_SEARCH_DEFAULT);
if (ret && INTEL_INFO(dev)->gen <= 4) {
return 0;
} else if (ret) {
compression_threshold <<= 1;
goto again;
} else {
return compression_threshold;
}
}
static int i915_setup_compression(struct drm_device *dev, int size)
static int i915_setup_compression(struct drm_device *dev, int size, int fb_cpp)
{
struct drm_i915_private *dev_priv = dev->dev_private;
struct drm_mm_node *uninitialized_var(compressed_llb);
int ret;
ret = find_compression_threshold(dev, &dev_priv->fbc.compressed_fb,
size);
size, fb_cpp);
if (!ret)
goto err_llb;
else if (ret > 1) {
DRM_INFO("Reducing the compressed framebuffer size. This may lead to less power savings than a non-reduced-size. Try to increase stolen memory size if available in BIOS.\n");
}
dev_priv->fbc.threshold = ret;
if (HAS_PCH_SPLIT(dev))
I915_WRITE(ILK_DPFC_CB_BASE, dev_priv->fbc.compressed_fb.start);
@ -157,7 +183,7 @@ static int i915_setup_compression(struct drm_device *dev, int size)
dev_priv->mm.stolen_base + compressed_llb->start);
}
dev_priv->fbc.size = size;
dev_priv->fbc.size = size / dev_priv->fbc.threshold;
DRM_DEBUG_KMS("reserved %d bytes of contiguous stolen space for FBC\n",
size);
@ -172,7 +198,7 @@ err_llb:
return -ENOSPC;
}
int i915_gem_stolen_setup_compression(struct drm_device *dev, int size)
int i915_gem_stolen_setup_compression(struct drm_device *dev, int size, int fb_cpp)
{
struct drm_i915_private *dev_priv = dev->dev_private;
@ -185,7 +211,7 @@ int i915_gem_stolen_setup_compression(struct drm_device *dev, int size)
/* Release any current block */
i915_gem_stolen_cleanup_compression(dev);
return i915_setup_compression(dev, size);
return i915_setup_compression(dev, size, fb_cpp);
}
void i915_gem_stolen_cleanup_compression(struct drm_device *dev)

30
drivers/gpu/drm/i915/intel_pm.c
View File

@ -229,9 +229,20 @@ static void ironlake_enable_fbc(struct drm_crtc *crtc)
dpfc_ctl = DPFC_CTL_PLANE(intel_crtc->plane);
if (drm_format_plane_cpp(fb->pixel_format, 0) == 2)
dev_priv->fbc.threshold++;
switch (dev_priv->fbc.threshold) {
case 4:
case 3:
dpfc_ctl |= DPFC_CTL_LIMIT_4X;
break;
case 2:
dpfc_ctl |= DPFC_CTL_LIMIT_2X;
else
break;
case 1:
dpfc_ctl |= DPFC_CTL_LIMIT_1X;
break;
}
dpfc_ctl |= DPFC_CTL_FENCE_EN;
if (IS_GEN5(dev))
dpfc_ctl |= obj->fence_reg;
@ -285,9 +296,21 @@ static void gen7_enable_fbc(struct drm_crtc *crtc)
dpfc_ctl = IVB_DPFC_CTL_PLANE(intel_crtc->plane);
if (drm_format_plane_cpp(fb->pixel_format, 0) == 2)
dev_priv->fbc.threshold++;
switch (dev_priv->fbc.threshold) {
case 4:
case 3:
dpfc_ctl |= DPFC_CTL_LIMIT_4X;
break;
case 2:
dpfc_ctl |= DPFC_CTL_LIMIT_2X;
else
break;
case 1:
dpfc_ctl |= DPFC_CTL_LIMIT_1X;
break;
}
dpfc_ctl |= IVB_DPFC_CTL_FENCE_EN;
I915_WRITE(ILK_DPFC_CONTROL, dpfc_ctl | DPFC_CTL_EN);
@ -567,7 +590,8 @@ void intel_update_fbc(struct drm_device *dev)
if (in_dbg_master())
goto out_disable;
if (i915_gem_stolen_setup_compression(dev, intel_fb->obj->base.size)) {
if (i915_gem_stolen_setup_compression(dev, intel_fb->obj->base.size,
drm_format_plane_cpp(fb->pixel_format, 0))) {
if (set_no_fbc_reason(dev_priv, FBC_STOLEN_TOO_SMALL))
DRM_DEBUG_KMS("framebuffer too large, disabling compression\n");
goto out_disable;