[Intel-gfx] [PATCH] drm/i915: Try harder to get FBC
Rodrigo Vivi
rodrigo.vivi at gmail.com
Tue Jul 1 18:09:28 CEST 2014
Jani, please ignore the 4th patch on this series and merge the 3 I've
reviewed and tested already.
They are essential to allow FBC work on BDW without changing bios
configuration and allow PC7 residency.
Thanks,
Rodrigo.
On Mon, Jun 30, 2014 at 10:41 AM, Rodrigo Vivi <rodrigo.vivi at intel.com>
wrote:
> From: Ben Widawsky <benjamin.widawsky at intel.com>
>
> 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).
>
> Reviewedby: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: Art Runyan <arthur.j.runyan at intel.com>
> Signed-off-by: Ben Widawsky <ben at bwidawsk.net>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> ---
> drivers/gpu/drm/i915/i915_drv.h | 3 +-
> drivers/gpu/drm/i915/i915_gem_stolen.c | 54
> +++++++++++++++++++++++++---------
> drivers/gpu/drm/i915/intel_pm.c | 30 +++++++++++++++++--
> 3 files changed, 69 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.h
> b/drivers/gpu/drm/i915/i915_drv.h
> index 5b7aed2..9953ea8 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -600,6 +600,7 @@ struct intel_context {
>
> struct i915_fbc {
> unsigned long size;
> + unsigned threshold;
> unsigned int fb_id;
> enum plane plane;
> int y;
> @@ -2489,7 +2490,7 @@ 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 *
> diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c
> b/drivers/gpu/drm/i915/i915_gem_stolen.c
> index a86b331..b695d18 100644
> --- a/drivers/gpu/drm/i915/i915_gem_stolen.c
> +++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
> @@ -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)
> + 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;
> - else
> +
> + 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)
> diff --git a/drivers/gpu/drm/i915/intel_pm.c
> b/drivers/gpu/drm/i915/intel_pm.c
> index a90fdbd..4fcb2f7 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -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);
> @@ -566,7 +589,8 @@ 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;
> --
> 1.9.1
>
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> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
--
Rodrigo Vivi
Blog: http://blog.vivi.eng.br
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