[Mesa-stable] [PATCH] i965: Fix check for negative pitch in can_do_fast_copy_blit().

[Kenneth Graunke]

At this point, the pitch is in bytes.  We haven't yet divided the pitch
by 4 for tiled surfaces, so abs(pitch) may be larger than 32K.  This
means the bit 15 trick won't work.

The caller now has signed integers anyway, so just pass those through
and do the obvious check.

Cc: "17.0" <mesa-stable at lists.freedesktop.org>
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/mesa/drivers/dri/i965/intel_blit.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/intel_blit.c b/src/mesa/drivers/dri/i965/intel_blit.c
index 9863ca1f94a..4d4ab911cbc 100644
--- a/src/mesa/drivers/dri/i965/intel_blit.c
+++ b/src/mesa/drivers/dri/i965/intel_blit.c
@@ -476,11 +476,11 @@ static bool
 can_fast_copy_blit(struct brw_context *brw,
 		   drm_intel_bo *src_buffer,
                    int16_t src_x, int16_t src_y,
-                   uintptr_t src_offset, uint32_t src_pitch,
+                   uintptr_t src_offset, int32_t src_pitch,
                    uint32_t src_tiling, uint32_t src_tr_mode,
 		   drm_intel_bo *dst_buffer,
                    int16_t dst_x, int16_t dst_y,
-                   uintptr_t dst_offset, uint32_t dst_pitch,
+                   uintptr_t dst_offset, int32_t dst_pitch,
                    uint32_t dst_tiling, uint32_t dst_tr_mode,
                    int16_t w, int16_t h, uint32_t cpp,
                    GLenum logic_op)
@@ -516,10 +516,8 @@ can_fast_copy_blit(struct brw_context *brw,
    if (!_mesa_is_pow_two(cpp) || cpp > 16)
       return false;
 
-   /* For Fast Copy Blits the pitch cannot be a negative number. So, bit 15
-    * of the destination pitch must be zero.
-    */
-   if ((src_pitch >> 15 & 1) != 0 || (dst_pitch >> 15 & 1) != 0)
+   /* For Fast Copy Blits the pitch cannot be a negative number. */
+   if (src_pitch < 0 || dst_pitch < 0)
       return false;
 
    /* For Linear surfaces, the pitch has to be an OWord (16byte) multiple. */
-- 
2.11.0