From 1e07dce2b9664861d92917426cbb153cc89a1c8d Mon Sep 17 00:00:00 2001
From: Peter Clifton <pcjc2@cam.ac.uk>
Date: Fri, 5 Nov 2010 14:26:24 +0000
Subject: [PATCH] intel: Fix emit_linear_blit to use DWORD aligned width blits
The width of the 2D blits used to copy the data is defined as a 16-bit
signed integer, but the pitch must be DWORD aligned. Limit to an integral
number of DWORDs, (1 << 15 - 4) rather than (1 << 15 -1).
Fixes corruption to data uploaded with glBufferSubData.
Signed-off-by: Peter Clifton <pcjc2@cam.ac.uk>
---
src/mesa/drivers/dri/intel/intel_blit.c | 7 +++++--
1 files changed, 5 insertions(+), 2 deletions(-)
@@ -483,8 +483,11 @@ 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 is a signed value. */
- pitch = MIN2(size, (1 << 15) - 1);
+ /* 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),
+ * rounding that down to the nearest DWORD is 1 << 15 - 4
+ */
+ pitch = MIN2(size, (1 << 15) - 4);
height = size / pitch;
ok = intelEmitCopyBlit(intel, 1,
pitch, src_bo, src_offset, I915_TILING_NONE,
--
1.7.1