shadow+dri2: Allow dri2 to be independently enabled with shadow

To enable DRI we create GEM buffers for the client to render into with
hardware acceleration. In order to maintain coherency between any 2D
render operations with the independent 3D clients (this includes the
reading of 2D rasterisation by the direct rendering client, e.g.
compiz using texture_from_pixmap) we need to replace the shadow pixmap
with the GTT mapping. Therefore 2D rendering to a DRI buffer will be to
uncached memory and thus penalised -- but the direct rendering clients
will have full hardware acceleration.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 170 insertions, 55 deletions

diff --git a/src/intel_dri.c b/src/intel_dri.c
index 98042722..1527dba1 100644
--- a/src/intel_dri.c
+++ b/src/intel_dri.c
@@ -58,6 +58,8 @@ USE OR OTHER DEALINGS IN THE SOFTWARE.
 #include "windowstr.h"
 #include "shadow.h"
 
+#include "xaarop.h"
+
 #include "intel.h"
 #include "i830_reg.h"
 
@@ -68,11 +70,101 @@ USE OR OTHER DEALINGS IN THE SOFTWARE.
 typedef struct {
 	int refcnt;
 	PixmapPtr pixmap;
+	DrawablePtr drawable;
 	unsigned int attachment;
 } I830DRI2BufferPrivateRec, *I830DRI2BufferPrivatePtr;
 
-#if DRI2INFOREC_VERSION < 2
+static PixmapPtr get_front_buffer(DrawablePtr drawable, DrawablePtr *ret)
+{
+	ScreenPtr screen = drawable->pScreen;
+	ScrnInfoPtr scrn = xf86Screens[screen->myNum];
+	intel_screen_private *intel = intel_get_screen_private(scrn);
+	PixmapPtr pixmap;
+
+	pixmap = get_drawable_pixmap(drawable);
+	if (pixmap_is_scanout(pixmap)) {
+		pixmap = fbCreatePixmap(screen, 0, 0, drawable->depth, 0);
+		if (pixmap) {
+			screen->ModifyPixmapHeader(pixmap,
+						   drawable->width,
+						   drawable->height,
+						   0, 0,
+						   intel->front_pitch,
+						   NULL);
+			intel_set_pixmap_bo(pixmap, intel->front_buffer);
+		}
+	} else if (intel_get_pixmap_bo(pixmap)) {
+		pixmap->refcnt++;
+		*ret = drawable;
+	} else
+		pixmap = NULL;
+	return pixmap;
+}
 
+static PixmapPtr fixup_shadow(DrawablePtr drawable, PixmapPtr pixmap)
+{
+	ScreenPtr screen = drawable->pScreen;
+	PixmapPtr old = get_drawable_pixmap(drawable);
+	struct intel_pixmap *priv = intel_get_pixmap_private(pixmap);
+	GCPtr gc;
+
+	/* With an active shadow buffer, 2D pixmaps are created in
+	 * system memory and GPU acceleration of 2D render operations
+	 * is *disabled*. As DRI is still enabled, we create hardware
+	 * buffers for the clients, and need to mix this with the
+	 * 2D rendering. So we replace the system pixmap with a GTT
+	 * mapping (with the kernel enforcing coherency between
+	 * CPU and GPU) for 2D and provide the bo so that clients
+	 * can write directly to it (or read from it in the case
+	 * of TextureFromPixmap) using the GPU.
+	 *
+	 * So for a compositor with a GL backend (i.e. compiz) we have
+	 * smooth wobbly windows but incur the cost of uncached 2D rendering,
+	 * however 3D applications (games and clutter) are still fully
+	 * accelerated.
+	 */
+
+	drm_intel_gem_bo_map_gtt(priv->bo);
+
+	/* Copy the current contents of the pixmap to the bo. */
+	gc = GetScratchGC(drawable->depth, screen);
+	if (gc) {
+		ValidateGC(&pixmap->drawable, gc);
+
+		screen->ModifyPixmapHeader(pixmap,
+					   drawable->width,
+					   drawable->height,
+					   0, 0,
+					   priv->stride,
+					   priv->bo->virtual);
+
+		gc->ops->CopyArea(drawable, &pixmap->drawable,
+				  gc,
+				  0, 0,
+				  drawable->width,
+				  drawable->height,
+				  0, 0);
+		FreeScratchGC(gc);
+	}
+
+	intel_set_pixmap_private(pixmap, NULL);
+	screen->DestroyPixmap(pixmap);
+
+	/* Redirect 2D rendering to the uncached GTT map of the bo */
+	screen->ModifyPixmapHeader(old,
+				   drawable->width,
+				   drawable->height,
+				   0, 0,
+				   priv->stride,
+				   priv->bo->virtual);
+
+	/* And redirect the pixmap to the new bo (for 3D). */
+	intel_set_pixmap_private(old, priv);
+	old->refcnt++;
+	return old;
+}
+
+#if DRI2INFOREC_VERSION < 2
 static DRI2BufferPtr
 I830DRI2CreateBuffers(DrawablePtr drawable, unsigned int *attachments,
 		      int count)
@@ -85,6 +177,7 @@ I830DRI2CreateBuffers(DrawablePtr drawable, unsigned int *attachments,
 	int i;
 	I830DRI2BufferPrivatePtr privates;
 	PixmapPtr pixmap, pDepthPixmap;
+	DrawablePtr target;
 
 	buffers = calloc(count, sizeof *buffers);
 	if (buffers == NULL)
@@ -97,39 +190,49 @@ I830DRI2CreateBuffers(DrawablePtr drawable, unsigned int *attachments,
 
 	pDepthPixmap = NULL;
 	for (i = 0; i < count; i++) {
+		target = NULL;
+		pixmap = NULL;
 		if (attachments[i] == DRI2BufferFrontLeft) {
-			pixmap = get_drawable_pixmap(drawable);
-			pixmap->refcnt++;
+			pixmap = get_front_buffer(drawable, &target);
 		} else if (attachments[i] == DRI2BufferStencil && pDepthPixmap) {
 			pixmap = pDepthPixmap;
 			pixmap->refcnt++;
-		} else {
-			unsigned int hint = 0;
-
-			switch (attachments[i]) {
-			case DRI2BufferDepth:
-				if (SUPPORTS_YTILING(intel))
-					hint = INTEL_CREATE_PIXMAP_TILING_Y;
-				else
-					hint = INTEL_CREATE_PIXMAP_TILING_X;
-				break;
-			case DRI2BufferFakeFrontLeft:
-			case DRI2BufferFakeFrontRight:
-			case DRI2BufferBackLeft:
-			case DRI2BufferBackRight:
-				hint = INTEL_CREATE_PIXMAP_TILING_X;
-				break;
+		}
+		if (pixmap == NULL) {
+			unsigned int hint = INTEL_CREATE_PIXMAP_DRI2;
+
+			if (intel->tiling) {
+				switch (attachments[i]) {
+				case DRI2BufferDepth:
+					if (SUPPORTS_YTILING(intel))
+						hint |= INTEL_CREATE_PIXMAP_TILING_Y;
+					else
+						hint |= INTEL_CREATE_PIXMAP_TILING_X;
+					break;
+				case DRI2BufferFakeFrontLeft:
+				case DRI2BufferFakeFrontRight:
+				case DRI2BufferBackLeft:
+				case DRI2BufferBackRight:
+					hint |= INTEL_CREATE_PIXMAP_TILING_X;
+					break;
+				}
 			}
 
-			if (!intel->tiling)
-				hint = 0;
-
 			pixmap = screen->CreatePixmap(screen,
 						      drawable->width,
 						      drawable->height,
 						      drawable->depth,
 						      hint);
+			if (pixmap == NULL ||
+			    intel_get_pixmap_bo(pixmap) == NULL)
+			{
+				if (pixmap)
+					screen->DestroyPixmap(pixmap);
+				goto unwind;
+			}
 
+			if (attachment == DRI2BufferFrontLeft)
+				pixmap = fixup_shadow(drawable, pixmap);
 		}
 
 		if (attachments[i] == DRI2BufferDepth)
@@ -144,6 +247,8 @@ I830DRI2CreateBuffers(DrawablePtr drawable, unsigned int *attachments,
 		privates[i].pixmap = pixmap;
 		privates[i].attachment = attachments[i];
 
+		privates[i].drawable = target ? target : &pixmap->drawable;
+
 		bo = intel_get_pixmap_bo(pixmap);
 		if (bo == NULL || dri_bo_flink(bo, &buffers[i].name) != 0) {
 			/* failed to name buffer */
@@ -193,6 +298,7 @@ I830DRI2CreateBuffer(DrawablePtr drawable, unsigned int attachment,
 	dri_bo *bo;
 	I830DRI2BufferPrivatePtr privates;
 	PixmapPtr pixmap;
+	DrawablePtr target = NULL;
 
 	buffer = calloc(1, sizeof *buffer);
 	if (buffer == NULL)
@@ -203,30 +309,25 @@ I830DRI2CreateBuffer(DrawablePtr drawable, unsigned int attachment,
 		return NULL;
 	}
 
-	if (attachment == DRI2BufferFrontLeft) {
-		pixmap = get_drawable_pixmap(drawable);
-		pixmap->refcnt++;
-	} else {
-		unsigned int hint = 0;
-
-		switch (attachment) {
-		case DRI2BufferDepth:
-		case DRI2BufferDepthStencil:
-			if (SUPPORTS_YTILING(intel))
-				hint = INTEL_CREATE_PIXMAP_TILING_Y;
-			else
-				hint = INTEL_CREATE_PIXMAP_TILING_X;
-			break;
-		case DRI2BufferFakeFrontLeft:
-		case DRI2BufferFakeFrontRight:
-		case DRI2BufferBackLeft:
-		case DRI2BufferBackRight:
-			hint = INTEL_CREATE_PIXMAP_TILING_X;
-			break;
-		}
+	pixmap = NULL;
+	if (attachment == DRI2BufferFrontLeft)
+		pixmap = get_front_buffer(drawable, &target);
+	if (pixmap == NULL) {
+		unsigned int hint = INTEL_CREATE_PIXMAP_DRI2;
 
-		if (!intel->tiling)
-			hint = 0;
+		if (intel->tiling) {
+			switch (attachment) {
+			case DRI2BufferDepth:
+			case DRI2BufferDepthStencil:
+				if (SUPPORTS_YTILING(intel)) {
+					hint |= INTEL_CREATE_PIXMAP_TILING_Y;
+					break;
+				}
+			default:
+				hint |= INTEL_CREATE_PIXMAP_TILING_X;
+				break;
+			}
+		}
 
 		pixmap = screen->CreatePixmap(screen,
 					      drawable->width,
@@ -234,12 +335,16 @@ I830DRI2CreateBuffer(DrawablePtr drawable, unsigned int attachment,
 					      (format != 0) ? format :
 							      drawable->depth,
 					      hint);
-		if (pixmap == NULL) {
+		if (pixmap == NULL || intel_get_pixmap_bo(pixmap) == NULL) {
+			if (pixmap)
+				screen->DestroyPixmap(pixmap);
 			free(privates);
 			free(buffer);
 			return NULL;
 		}
 
+		if (attachment == DRI2BufferFrontLeft)
+			pixmap = fixup_shadow(drawable, pixmap);
 	}
 
 	buffer->attachment = attachment;
@@ -251,6 +356,7 @@ I830DRI2CreateBuffer(DrawablePtr drawable, unsigned int attachment,
 	privates->refcnt = 1;
 	privates->pixmap = pixmap;
 	privates->attachment = attachment;
+	privates->drawable = target ? target : &pixmap->drawable;
 
 	bo = intel_get_pixmap_bo(pixmap);
 	if (bo == NULL || dri_bo_flink(bo, &buffer->name) != 0) {
@@ -298,11 +404,10 @@ I830DRI2CopyRegion(DrawablePtr drawable, RegionPtr pRegion,
 	ScreenPtr screen = drawable->pScreen;
 	ScrnInfoPtr scrn = xf86Screens[screen->myNum];
 	intel_screen_private *intel = intel_get_screen_private(scrn);
-	DrawablePtr src = (srcPrivate->attachment == DRI2BufferFrontLeft)
-	    ? drawable : &srcPrivate->pixmap->drawable;
-	DrawablePtr dst = (dstPrivate->attachment == DRI2BufferFrontLeft)
-	    ? drawable : &dstPrivate->pixmap->drawable;
+	DrawablePtr src = srcPrivate->drawable;
+	DrawablePtr dst = dstPrivate->drawable;
 	RegionPtr pCopyClip;
+	PixmapPtr src_pixmap, dst_pixmap;
 	GCPtr gc;
 
 	gc = GetScratchGC(dst->depth, screen);
@@ -399,12 +504,22 @@ I830DRI2CopyRegion(DrawablePtr drawable, RegionPtr pRegion,
 	 * that will happen before the client tries to render
 	 * again. */
 
-	(*gc->ops->CopyArea) (src, dst,
-			       gc,
-			       0, 0,
-			       drawable->width, drawable->height,
-			       0, 0);
+	/* Re-enable 2D acceleration... */
+	src_pixmap = get_drawable_pixmap(src);
+	src_pixmap->devPrivate.ptr = NULL;
+
+	dst_pixmap = get_drawable_pixmap(dst);
+	dst_pixmap->devPrivate.ptr = NULL;
+
+	gc->ops->CopyArea(src, dst, gc,
+			  0, 0,
+			  drawable->width, drawable->height,
+			  0, 0);
 	FreeScratchGC(gc);
+
+	/* and restore 2D/3D coherency */
+	src_pixmap->devPrivate.ptr = intel_get_pixmap_bo(src_pixmap)->virtual;
+	dst_pixmap->devPrivate.ptr = intel_get_pixmap_bo(dst_pixmap)->virtual;
 }
 
 #if DRI2INFOREC_VERSION >= 4