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-rw-r--r--src/mesa/drivers/dri/intel/intel_tex_copy.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/src/mesa/drivers/dri/intel/intel_tex_copy.c b/src/mesa/drivers/dri/intel/intel_tex_copy.c
index 1af7b1c5671..c9cbcf480d5 100644
--- a/src/mesa/drivers/dri/intel/intel_tex_copy.c
+++ b/src/mesa/drivers/dri/intel/intel_tex_copy.c
@@ -70,6 +70,27 @@ intel_copy_texsubimage(struct intel_context *intel,
assert(region);
}
+ /* According to the Ivy Bridge PRM, Vol1 Part4, section 1.2.1.2 (Graphics
+ * Data Size Limitations):
+ *
+ * The BLT engine is capable of transferring very large quantities of
+ * graphics data. Any graphics data read from and written to the
+ * destination is permitted to represent a number of pixels that
+ * occupies up to 65,536 scan lines and up to 32,768 bytes per scan line
+ * at the destination. The maximum number of pixels that may be
+ * represented per scan line’s worth of graphics data depends on the
+ * color depth.
+ *
+ * Furthermore, intelEmitCopyBlit (which is called below) uses a signed
+ * 16-bit integer to represent buffer pitch, so it can only handle buffer
+ * pitches < 32k.
+ *
+ * As a result of these two limitations, we can only use the blitter to do
+ * this copy when the region's pitch is less than 32k.
+ */
+ if (region->pitch >= 32768)
+ return false;
+
if (intelImage->base.Base.TexObject->Target == GL_TEXTURE_1D_ARRAY ||
intelImage->base.Base.TexObject->Target == GL_TEXTURE_2D_ARRAY) {
perf_debug("no support for array textures\n");