[PATCH 2/2] Correct BO allocation alignment

Keith Packard
2014-09-10T21:09:09Z

BO allocations for pixmaps must be aligned to the tile height, but at
some point the code was changed to align them to twice the tile
height. This overallocates pixmaps, wasting memory, but more
importantly, for buffers allocated by DRM and shared through DRI3, the
stricter alignment check causes sharing to fail.

>From reading through the history of the code and related bugs, it
seems like this change was part of a set of changes trying to address
what turned out to be a kernel regression. Reverting this change
solves the DRI3 problem and saves a bit of memory for pixmap
allocations.

Signed-off-by: Keith Packard <keithp-aN4HjG94KOLQT0dZR+AlfA@public.gmane.org>
---
src/uxa/intel_uxa.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/uxa/intel_uxa.c b/src/uxa/intel_uxa.c
index d33eca5..4ce6eae 100644
--- a/src/uxa/intel_uxa.c
+++ b/src/uxa/intel_uxa.c
@@ -206,7 +206,7 @@ intel_uxa_compute_size(struct intel_screen_private *intel,
tile_height = 8;
else
tile_height = 32;
- aligned_h = ALIGN(h, 2*tile_height);
+ aligned_h = ALIGN(h, tile_height);

*stride = intel_get_fence_pitch(intel,
ALIGN(pitch, 512),
@@ -768,7 +768,7 @@ free_priv:
else
height = 32;

- height = ALIGN(pixmap->drawable.height, 2*height);
+ height = ALIGN(pixmap->drawable.height, height);
size = intel_get_fence_size(intel, priv->stride * height);
} else
size = priv->stride * pixmap->drawable.height;
--
2.0.1