[PATCH 4/4] drm/i915: Implement proper clipping for video sprites

ville.syrjala at linux.intel.com ville.syrjala at linux.intel.com
Thu Feb 21 13:35:03 PST 2013


From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Properly clip the source when the destination gets clipped
by the pipe dimensions.

Sadly the video sprite hardware is rather limited so it can't do proper
sub-pixel postitioning. Resort to truncating the source coordinates to
(macro)pixel boundary.

The scaling checks are done using the relaxed drm_region functions.
That means that the src/dst regions are reduced in size in order to keep
the scaling factor within the limits.

Also do some additional checking against various hardware limits.

v2: Truncate src coords instead of rounding to avoid increasing src
    viewport size, and adapt to changes in drm_calc_{h,v}scale().

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_sprite.c | 184 +++++++++++++++++++++++++++---------
 1 file changed, 138 insertions(+), 46 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_sprite.c b/drivers/gpu/drm/i915/intel_sprite.c
index d086e48..57001c4 100644
--- a/drivers/gpu/drm/i915/intel_sprite.c
+++ b/drivers/gpu/drm/i915/intel_sprite.c
@@ -32,6 +32,7 @@
 #include <drm/drmP.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_fourcc.h>
+#include <drm/drm_region.h>
 #include "intel_drv.h"
 #include <drm/i915_drm.h>
 #include "i915_drv.h"
@@ -415,6 +416,20 @@ ilk_get_colorkey(struct drm_plane *plane, struct drm_intel_sprite_colorkey *key)
 		key->flags = I915_SET_COLORKEY_NONE;
 }
 
+static bool
+format_is_yuv(uint32_t format)
+{
+	switch (format) {
+	case DRM_FORMAT_YUYV:
+	case DRM_FORMAT_UYVY:
+	case DRM_FORMAT_VYUY:
+	case DRM_FORMAT_YVYU:
+		return true;
+	default:
+		return false;
+	}
+}
+
 static int
 intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 		   struct drm_framebuffer *fb, int crtc_x, int crtc_y,
@@ -432,28 +447,51 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 	enum transcoder cpu_transcoder = intel_pipe_to_cpu_transcoder(dev_priv,
 								      pipe);
 	int ret = 0;
-	int x = src_x >> 16, y = src_y >> 16;
 	int primary_w = crtc->mode.hdisplay, primary_h = crtc->mode.vdisplay;
 	bool disable_primary = false;
+	bool visible;
+	int hscale, vscale;
+	int max_scale, min_scale;
+	int pixel_size = drm_format_plane_cpp(fb->pixel_format, 0);
+	struct drm_region src = {
+		.x1 = src_x,
+		.x2 = src_x + src_w,
+		.y1 = src_y,
+		.y2 = src_y + src_h,
+	};
+	struct drm_region dst = {
+		.x1 = crtc_x,
+		.x2 = crtc_x + crtc_w,
+		.y1 = crtc_y,
+		.y2 = crtc_y + crtc_h,
+	};
+	const struct drm_region clip = {
+		.x2 = crtc->mode.hdisplay,
+		.y2 = crtc->mode.vdisplay,
+	};
 
 	intel_fb = to_intel_framebuffer(fb);
 	obj = intel_fb->obj;
 
 	old_obj = intel_plane->obj;
 
-	src_w = src_w >> 16;
-	src_h = src_h >> 16;
-
 	/* Pipe must be running... */
-	if (!(I915_READ(PIPECONF(cpu_transcoder)) & PIPECONF_ENABLE))
-		return -EINVAL;
-
-	if (crtc_x >= primary_w || crtc_y >= primary_h)
+	if (!(I915_READ(PIPECONF(cpu_transcoder)) & PIPECONF_ENABLE)) {
+		DRM_DEBUG_KMS("Pipe disabled\n");
 		return -EINVAL;
+	}
 
 	/* Don't modify another pipe's plane */
-	if (intel_plane->pipe != intel_crtc->pipe)
+	if (intel_plane->pipe != intel_crtc->pipe) {
+		DRM_DEBUG_KMS("Wrong plane <-> crtc mapping\n");
 		return -EINVAL;
+	}
+
+	/* FIXME check all gen limits */
+	if (fb->width < 3 || fb->height < 3 || fb->pitches[0] > 16384) {
+		DRM_DEBUG_KMS("Unsuitable framebuffer for plane\n");
+		return -EINVAL;
+	}
 
 	/* Sprite planes can be linear or x-tiled surfaces */
 	switch (obj->tiling_mode) {
@@ -461,53 +499,104 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 		case I915_TILING_X:
 			break;
 		default:
+			DRM_DEBUG_KMS("Unsupported tiling mode\n");
 			return -EINVAL;
 	}
 
 	/*
-	 * Clamp the width & height into the visible area.  Note we don't
-	 * try to scale the source if part of the visible region is offscreen.
-	 * The caller must handle that by adjusting source offset and size.
+	 * FIXME the following code does a bunch of fuzzy adjustments to the
+	 * coordinates and sizes. We probably need some way to decide whether
+	 * more strict checking should be done instead.
 	 */
-	if ((crtc_x < 0) && ((crtc_x + crtc_w) > 0)) {
-		crtc_w += crtc_x;
-		crtc_x = 0;
+	max_scale = intel_plane->max_downscale << 16;
+	min_scale = intel_plane->can_scale ? 1 : (1 << 16);
+
+	hscale = drm_calc_hscale_relaxed(&src, &dst, min_scale, max_scale);
+	BUG_ON(hscale < 0);
+
+	vscale = drm_calc_vscale_relaxed(&src, &dst, min_scale, max_scale);
+	BUG_ON(vscale < 0);
+
+	visible = drm_region_clip_scaled(&src, &dst, &clip, hscale, vscale);
+
+	if (visible) {
+		/* check again in case clipping clamped the results */
+		hscale = drm_calc_hscale(&src, &dst, min_scale, max_scale);
+		if (hscale < 0) {
+			DRM_DEBUG_KMS("Horizontal scaling factor out of limits\n");
+			drm_region_debug(&src, true);
+			drm_region_debug(&dst, false);
+			return hscale;
+		}
+
+		vscale = drm_calc_vscale(&src, &dst, min_scale, max_scale);
+		if (vscale < 0) {
+			DRM_DEBUG_KMS("Vertical scaling factor out of limits\n");
+			drm_region_debug(&src, true);
+			drm_region_debug(&dst, false);
+			return vscale;
+		}
+
+		/* Make the source viewport size an exact multiple of the scaling factors. */
+		drm_region_adjust_size(&src,
+				       drm_region_width(&dst) * hscale - drm_region_width(&src),
+				       drm_region_height(&dst) * vscale - drm_region_height(&src));
+
+		crtc_x = dst.x1;
+		crtc_y = dst.y1;
+		crtc_w = drm_region_width(&dst);
+		crtc_h = drm_region_height(&dst);
+
+		/*
+		 * Hardware doesn't handle subpixel coordinates.
+		 * Adjust to (macro)pixel boundary, but be careful not to
+		 * increase the source viewport size, because that could
+		 * push the downscaling factor out of bounds.
+		 */
+		src_x = src.x1 >> 16;
+		src_w = drm_region_width(&src) >> 16;
+		src_y = src.y1 >> 16;
+		src_h = drm_region_height(&src) >> 16;
+
+		if (format_is_yuv(fb->pixel_format)) {
+			src_x &= ~1;
+			src_w &= ~1;
+		}
 	}
-	if ((crtc_x + crtc_w) <= 0) /* Nothing to display */
-		goto out;
-	if ((crtc_x + crtc_w) > primary_w)
-		crtc_w = primary_w - crtc_x;
-
-	if ((crtc_y < 0) && ((crtc_y + crtc_h) > 0)) {
-		crtc_h += crtc_y;
-		crtc_y = 0;
+
+	/* Account for minimum size when scaling */
+	if (visible && (src_w != crtc_w || src_h != crtc_h)) {
+		BUG_ON(!intel_plane->can_scale);
+
+		/* FIXME interlacing min height is 6 */
+		/* FIXME return an error instead? */
+
+		if (crtc_w < 3 || crtc_h < 3)
+			visible = false;
+
+		if (src_w < 3 || src_h < 3)
+			visible = false;
 	}
-	if ((crtc_y + crtc_h) <= 0) /* Nothing to display */
-		goto out;
-	if (crtc_y + crtc_h > primary_h)
-		crtc_h = primary_h - crtc_y;
 
-	if (!crtc_w || !crtc_h) /* Again, nothing to display */
-		goto out;
+	/* Check size restrictions when scaling */
+	if (visible && (src_w != crtc_w || src_h != crtc_h)) {
+		unsigned int width_bytes = ((src_x * pixel_size) & 63) + src_w * pixel_size;
 
-	/*
-	 * We may not have a scaler, eg. HSW does not have it any more
-	 */
-	if (!intel_plane->can_scale && (crtc_w != src_w || crtc_h != src_h))
-		return -EINVAL;
+		BUG_ON(!intel_plane->can_scale);
 
-	/*
-	 * We can take a larger source and scale it down, but
-	 * only so much...  16x is the max on SNB.
-	 */
-	if (((src_w * src_h) / (crtc_w * crtc_h)) > intel_plane->max_downscale)
-		return -EINVAL;
+		if (src_w > 2048 || src_h > 2048 ||
+		    width_bytes > 4096 || fb->pitches[0] > 4096) {
+			DRM_DEBUG_KMS("Source dimensions exceed hardware limits\n");
+			return -EINVAL;
+		}
+	}
 
 	/*
 	 * If the sprite is completely covering the primary plane,
 	 * we can disable the primary and save power.
 	 */
-	if ((crtc_x == 0) && (crtc_y == 0) &&
+	if (visible &&
+	    (crtc_x == 0) && (crtc_y == 0) &&
 	    (crtc_w == primary_w) && (crtc_h == primary_h))
 		disable_primary = true;
 
@@ -526,11 +615,15 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 	if (!disable_primary)
 		intel_enable_primary(crtc);
 
-	intel_plane->update_plane(plane, fb, obj, crtc_x, crtc_y,
-				  crtc_w, crtc_h, x, y, src_w, src_h);
+	if (visible) {
+		intel_plane->update_plane(plane, fb, obj,
+					  crtc_x, crtc_y, crtc_w, crtc_h,
+					  src_x, src_y, src_w, src_h);
 
-	if (disable_primary)
-		intel_disable_primary(crtc);
+		if (disable_primary)
+			intel_disable_primary(crtc);
+	} else
+		intel_plane->disable_plane(plane);
 
 	/* Unpin old obj after new one is active to avoid ugliness */
 	if (old_obj) {
@@ -550,7 +643,6 @@ intel_update_plane(struct drm_plane *plane, struct drm_crtc *crtc,
 
 out_unlock:
 	mutex_unlock(&dev->struct_mutex);
-out:
 	return ret;
 }
 
-- 
1.7.12.4



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