intel: Add assert check for blitting alignment.

Also fixup code comment to reflect that the GPU requires DWORD
alignment, but in this case does not actually pass the value "in
DWORDs" as I previously stated.

diff --git a/src/mesa/drivers/dri/intel/intel_blit.c b/src/mesa/drivers/dri/intel/intel_blit.c
index 711889883067f0363ee234ed4c2c8d4f8f262d6b..c2917e9b07e79847a7ba4fb94f29669b3dd06fc2 100644 (file)
--- a/src/mesa/drivers/dri/intel/intel_blit.c
+++ b/src/mesa/drivers/dri/intel/intel_blit.c
@@ -483,8 +483,8 @@ intel_emit_linear_blit(struct intel_context *intel,
    /* Blits are in a different ringbuffer so we don't use them. */
    assert(intel->gen < 6);
 
-   /* The pitch hits the GPU as a is a signed value, IN DWORDs.
-    * But we want width to match pitch. Max width is (1 << 15 - 1),
+   /* The pitch given to the GPU must be DWORD aligned, and
+    * we want width to match pitch. Max width is (1 << 15 - 1),
     * rounding that down to the nearest DWORD is 1 << 15 - 4
     */
    pitch = MIN2(size, (1 << 15) - 4);
@@ -502,6 +502,7 @@ intel_emit_linear_blit(struct intel_context *intel,
    dst_offset += pitch * height;
    size -= pitch * height;
    assert (size < (1 << 15));
+   assert ((size & 3) == 0); /* Pitch must be DWORD aligned */
    if (size != 0) {
       ok = intelEmitCopyBlit(intel, 1,
                             size, src_bo, src_offset, I915_TILING_NONE,