Before this commit, if a client were to request a stencil or hiz buffer, then
I830DRI2CreateBuffer() allocated and returned an X-tiled buffer by
accident. (DRI2BufferStencil and DRI2BufferHiz were unintentionally caught
by the default case of a switch statement.)
Now, I830DRI2CreateBuffer() correctly returns a Y-tiled buffer and handles
the stencil buffer as a special case due its quirky pitch requirements.
This shouldn't break older Mesa versions, because they never query (via
DRI2GetBuffersWithFormat) for the drawable's DRI2BufferStencil.
Signed-off-by: Chad Versace <c...@chad-versace.us>
---
src/intel_dri.c | 30 ++++++++++++++++++++++++++----
1 files changed, 26 insertions(+), 4 deletions(-)
diff --git a/src/intel_dri.c b/src/intel_dri.c
index 48d0f56..4bcec45 100644
--- a/src/intel_dri.c
+++ b/src/intel_dri.c
@@ -329,11 +329,16 @@ I830DRI2CreateBuffer(DrawablePtr drawable, unsigned int
attachment,
pixmap = get_front_buffer(drawable);
if (pixmap == NULL) {
unsigned int hint = INTEL_CREATE_PIXMAP_DRI2;
+ int pixmap_width = drawable->width;
+ int pixmap_height = drawable->height;
+ int pixmap_cpp = (format != 0) ? format : drawable->depth;
if (intel->tiling & INTEL_TILING_3D) {
switch (attachment) {
case DRI2BufferDepth:
case DRI2BufferDepthStencil:
+ case DRI2BufferStencil:
+ case DRI2BufferHiz:
if (SUPPORTS_YTILING(intel)) {
hint |= INTEL_CREATE_PIXMAP_TILING_Y;
break;
@@ -344,11 +349,28 @@ I830DRI2CreateBuffer(DrawablePtr drawable, unsigned int
attachment,
}
}
+ /*
+ * The stencil buffer has quirky pitch requirements. From Vol
+ * 2a, 11.5.6.2.1 3DSTATE_STENCIL_BUFFER, field "Surface
+ * Pitch":
+ * The pitch must be set to 2x the value computed based on
+ * width, as the stencil buffer is stored with two rows
+ * interleaved.
+ * To accomplish this, we resort to the nasty hack of doubling
+ * the drm region's cpp and halving its height.
+ *
+ * If we neglect to double the pitch, then
+ * drm_intel_gem_bo_map_gtt() maps the memory incorrectly.
+ */
+ if (attachment == DRI2BufferStencil) {
+ pixmap_height /= 2;
+ pixmap_cpp *= 2;
+ }
+
pixmap = screen->CreatePixmap(screen,
- drawable->width,
- drawable->height,
- (format != 0) ? format :
- drawable->depth,
+ pixmap_width,
+ pixmap_height,
+ pixmap_cpp,
hint);
if (pixmap == NULL || intel_get_pixmap_bo(pixmap) == NULL) {
if (pixmap)
--
1.7.5.2
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