On 05/04/2018 05:59 PM, Nanley Chery wrote:
On Fri, May 04, 2018 at 09:03:32AM +0300, Tapani Pälli wrote:
Hi Nanley;
Hey Tapani,
On 05/03/2018 10:03 PM, Nanley Chery wrote:
Before this patch, if we failed to initialize an MCS buffer, we'd
end up in a state in which the miptree thinks it has an MCS buffer,
but doesn't. We also leaked the clear_color_bo if it existed.
With this patch, we now free the miptree aux buffer resources and let
intel_miptree_alloc_mcs() know that the MCS buffer no longer exists.
I triggered this by forcing the failure (by inserting 1 instead unlikely(map
==NULL) to mcs buffer map condition) and following happens currently:
Thanks for testing this! It'd be great if we could have a piglit test
that would trigger this case for us, but it's not clear to me what that
would look like.
--- 8< ---
Failed to map mcs buffer into GTT
deqp-egl: ../src/intel/blorp/blorp_clear.c:313: blorp_fast_clear: Assertion
`start_layer + num_layers <= MAX2(surf->aux_surf->logical_level0_px.depth >>
level, surf->aux_surf->logical_level0_px.array_len)' failed.
Aborted (core dumped)
I can confirm a similar assertion with piglit's
arb_clear_texture-multisample. What's happening here is that
blorp_fast_clear is receiving garbage aux surfaces, which causes it to
randomly trigger different assertions.
--- 8< ---
However even with this fix it seems we will end up in same or similar case
(segfault happening in do_single_blorp_clear):
--- 8< ---
Failed to map mcs buffer into GTT
Segmentation fault (core dumped)
--- 8< ---
Test case used was:
dEQP-EGL.functional.color_clears.single_context.gles2.rgba8888_window
This is interesting. What happens here is that we enter
do_single_blorp_clear() with irb->mt == NULL and we segfault at:
if (irb->Base.Base.Format != irb->mt->format)
It looks like some callers of intel_miptree_create() don't handle
failure well. Maybe they should throw an EGL error? Here's the backtrace
from the failed init:
#0 intel_miptree_init_mcs
#1 intel_miptree_alloc_mcs
#2 intel_miptree_alloc_aux
#3 intel_miptree_create
#4 intel_miptree_create_for_renderbuffer
#5 intel_update_winsys_renderbuffer_miptree
#6 intel_update_image_buffer
Problem is that the error propagation stops around here,
intel_update_image_buffer (or intel_prepare_render) so there's no way
currently for EGL to know.
However, this patch makes sense to me and makes the overall state
cleaner so that we could actually propagate error if wanted;
Reviewed-by: Tapani Pälli <tapani.pa...@intel.com>
#7 intel_update_image_buffers
#8 intel_update_renderbuffers
#9 intel_prepare_render
#10 intelMakeCurrent
#11 driBindContext
#12 ?? () from /usr/lib/libEGL_mesa.so.0
#13 eglMakeCurrent
#14 ?? () from /usr/lib/libEGL.so
#15 ?? () from /usr/lib/libEGL.so
#16 deqp::egl::SingleThreadColorClearCase::executeForContexts
#17 deqp::egl::MultiContextRenderCase::executeForSurface
#18 deqp::egl::RenderCase::executeForConfig
#19 deqp::egl::SimpleConfigCase::iterate
#20 tcu::TestSessionExecutor::iterateTestCase
#21 tcu::TestSessionExecutor::iterate
#22 tcu::App::iterate
#23 main (argc=<optimized out>, argv=<optimized out>)
Are we expected to survive without mcs?
I think it depends. Once we determine that we can enable MCS for a
miptree, we require that the aux buffer exist in order to successfully
create the miptree. In GL, if we can't successfully create a miptree, we
can throw a GL_OUT_OF_MEMORY error, and have mostly undefined behavior
for the rest of our existence. In EGL however, I think we can throw an
error that's not EGL_BAD_CONTEXT and carry on.
-Nanley
Cc: <mesa-sta...@lists.freedesktop.org>
---
src/mesa/drivers/dri/i965/intel_mipmap_tree.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
index b9a564552df..377efae32c9 100644
--- a/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
+++ b/src/mesa/drivers/dri/i965/intel_mipmap_tree.c
@@ -1658,7 +1658,7 @@ intel_miptree_copy_teximage(struct brw_context *brw,
intel_obj->needs_validate = true;
}
-static void
+static bool
intel_miptree_init_mcs(struct brw_context *brw,
struct intel_mipmap_tree *mt,
int init_value)
@@ -1678,13 +1678,14 @@ intel_miptree_init_mcs(struct brw_context *brw,
void *map = brw_bo_map(brw, mt->aux_buf->bo, MAP_WRITE | MAP_RAW);
if (unlikely(map == NULL)) {
fprintf(stderr, "Failed to map mcs buffer into GTT\n");
- brw_bo_unreference(mt->aux_buf->bo);
- free(mt->aux_buf);
- return;
+ intel_miptree_aux_buffer_free(mt->aux_buf);
+ mt->aux_buf = NULL;
+ return false;
}
void *data = map;
memset(data, init_value, mt->aux_buf->size);
brw_bo_unmap(mt->aux_buf->bo);
+ return true;
}
static struct intel_miptree_aux_buffer *
@@ -1764,15 +1765,14 @@ intel_miptree_alloc_mcs(struct brw_context *brw,
const uint32_t alloc_flags = 0;
mt->aux_buf = intel_alloc_aux_buffer(brw, "mcs-miptree",
&temp_mcs_surf, alloc_flags, mt);
- if (!mt->aux_buf) {
+ if (!mt->aux_buf ||
+ !intel_miptree_init_mcs(brw, mt, 0xFF)) {
free(aux_state);
return false;
}
mt->aux_state = aux_state;
- intel_miptree_init_mcs(brw, mt, 0xFF);
-
return true;
}
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