Add an option to verify at the point of migration that pixmaps which aren't

    marked dirty are in fact not dirty. This will hopefully help catch
    issues like the previous commit. Leave it on in fakexa.

2 files changed, 44 insertions, 0 deletions

diff --git a/exa/exa_migration.c b/exa/exa_migration.c
index ef7cfd86e..8077f6802 100644
--- a/exa/exa_migration.c
+++ b/exa/exa_migration.c
@@ -407,6 +407,36 @@ exaMigrateTowardSys (PixmapPtr pPixmap)
 }
 
 /**
+ * If the pixmap has both a framebuffer and system memory copy, this function
+ * asserts that both of them are the same.
+ */
+static void
+exaAssertNotDirty (PixmapPtr pPixmap)
+{
+    ExaPixmapPriv (pPixmap);
+    CARD8 *dst, *src;
+    int dst_pitch, src_pitch, data_row_bytes, y;
+
+    if (pExaPixmap == NULL || pExaPixmap->fb_ptr == NULL)
+	return;
+
+    dst = pExaPixmap->sys_ptr;
+    dst_pitch = pExaPixmap->sys_pitch;
+    src = pExaPixmap->fb_ptr;
+    src_pitch = pExaPixmap->fb_pitch;
+    data_row_bytes = pPixmap->drawable.width *
+		     pPixmap->drawable.bitsPerPixel / 8;
+
+    exaPrepareAccess(&pPixmap->drawable, EXA_PREPARE_SRC);
+    for (y = 0; y < pPixmap->drawable.height; y++) {
+	if (memcmp(dst, src, data_row_bytes) != 0) {
+	     abort();
+	}
+    }
+    exaFinishAccess(&pPixmap->drawable, EXA_PREPARE_SRC);
+}
+
+/**
  * Performs migration of the pixmaps according to the operation information
  * provided in pixmaps and can_accel and the migration scheme chosen in the
  * config file.
@@ -418,6 +448,19 @@ exaDoMigration (ExaMigrationPtr pixmaps, int npixmaps, Bool can_accel)
     ExaScreenPriv(pScreen);
     int i, j;
 
+    /* If this debugging flag is set, check each pixmap for whether it is marked
+     * as clean, and if so, actually check if that's the case.  This should help
+     * catch issues with failing to mark a drawable as dirty.  While it will
+     * catch them late (after the operation happened), it at least explains what
+     * went wrong, and instrumenting the code to find what operation happened
+     * to the pixmap last shouldn't be hard.
+     */
+    if (pExaScr->checkDirtyCorrectness) {
+	for (i = 0; i < npixmaps; i++) {
+	    if (!exaPixmapIsDirty (pixmaps[i].pPix))
+		exaAssertNotDirty (pixmaps[i].pPix);
+	}
+    }
     /* If anything is pinned in system memory, we won't be able to
      * accelerate.
      */
diff --git a/exa/exa_priv.h b/exa/exa_priv.h
index 89f8b0c9d..42c2f2d26 100644
--- a/exa/exa_priv.h
+++ b/exa/exa_priv.h
@@ -108,6 +108,7 @@ typedef struct {
     Bool			 swappedOut;
     enum ExaMigrationHeuristic	 migration;
     Bool			 hideOffscreenPixmapData;
+    Bool			 checkDirtyCorrectness;
 } ExaScreenPrivRec, *ExaScreenPrivPtr;
 
 /*