On 21 July 2012 17:36, Chad Versace <<a href="mailto:chad.versace@linux.intel.com" target="_blank">chad.versace@linux.intel.com</a>> wrote: <div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Immediately after obtaining, with DRI2GetBuffersWithFormat, the DRM buffer handle for a DRI2 buffer, we wrap that DRM buffer handle with a region and a miptre. This patch additionally allocates an accompanying multisample </blockquote><div> "miptree" </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> miptree if the DRI2 buffer is multisampled. Since we do not yet advertise multisample GL configs, the code for allocating the multisample miptree is currently inactive. CC: Eric Anholt <<a href="mailto:eric@anholt.net" target="_blank">eric@anholt.net</a>> CC: Paul Berry <<a href="mailto:stereotype441@gmail.com" target="_blank">stereotype441@gmail.com</a>> Signed-off-by: Chad Versace <<a href="mailto:chad.versace@linux.intel.com" target="_blank">chad.versace@linux.intel.com</a>> --- src/mesa/drivers/dri/intel/intel_context.c | 26 +++++++++---- src/mesa/drivers/dri/intel/intel_mipmap_tree.c | 52 ++++++++++++++++++++++++++ src/mesa/drivers/dri/intel/intel_mipmap_tree.h | 6 +++ 3 files changed, 76 insertions(+), 8 deletions(-) diff --git a/src/mesa/drivers/dri/intel/intel_context.c b/src/mesa/drivers/dri/intel/intel_context.c index 378859c..9a85d83 100644 --- a/src/mesa/drivers/dri/intel/intel_context.c +++ b/src/mesa/drivers/dri/intel/intel_context.c @@ -893,14 +893,24 @@ intel_process_dri2_buffer(struct intel_context *intel, if (!rb) return; + unsigned num_samples = rb->Base.Base.NumSamples; + /* We try to avoid closing and reopening the same BO name, because the first * use of a mapping of the buffer involves a bunch of page faulting which is * moderately expensive. */ - if (rb->mt && - rb->mt->region && - rb->mt->region->name == buffer->name) - return; + if (num_samples == 0) { + if (rb->mt && + rb->mt->region && + rb->mt->region->name == buffer->name) + return; + } else { + if (rb->mt && + rb->mt->singlesample_mt && + rb->mt->singlesample_mt->region && + rb->mt->singlesample_mt->region->name == buffer->name) + return; + } if (unlikely(INTEL_DEBUG & DEBUG_DRI)) { fprintf(stderr, @@ -920,9 +930,9 @@ intel_process_dri2_buffer(struct intel_context *intel, if (!region) return; - rb->mt = intel_miptree_create_for_region(intel, - GL_TEXTURE_2D, - intel_rb_format(rb), - region); + rb->mt = intel_miptree_create_for_dri2_buffer(intel, + intel_rb_format(rb), + num_samples, + region); intel_region_release(&region); } diff --git a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c index b402099..c4496ea 100644 --- a/src/mesa/drivers/dri/intel/intel_mipmap_tree.c +++ b/src/mesa/drivers/dri/intel/intel_mipmap_tree.c @@ -324,6 +324,58 @@ compute_msaa_layout(struct intel_context *intel, gl_format format) } } +/** + * If the DRI2 buffer is multisampled, then its content is undefined + * after calling this. This behavior violates the GLX spec for the + * benefit of avoiding a performance penalty. + */ +struct intel_mipmap_tree* +intel_miptree_create_for_dri2_buffer(struct intel_context *intel, + gl_format format, + uint32_t num_samples, + struct intel_region *region) +{ + struct intel_mipmap_tree *singlesample_mt = NULL; + struct intel_mipmap_tree *multisample_mt = NULL; + GLenum base_format = _mesa_get_format_base_format(format); + + /* Only the front and back buffers, which are color buffers, are shared + * through DRI2. + */ + assert(base_format == GL_RGB || base_format == GL_RGBA); + + singlesample_mt = intel_miptree_create_for_region(intel, GL_TEXTURE_2D, + format, region); + if (!singlesample_mt) + return NULL; + + if (num_samples == 0) { + return singlesample_mt; + } else { + multisample_mt = intel_miptree_create_for_renderbuffer(intel, + format, + region->width, + region->height, + num_samples); + if (!multisample_mt) { + intel_miptree_release(&singlesample_mt); + return NULL; + } + + multisample_mt->singlesample_mt = singlesample_mt; + multisample_mt->need_downsample = false; + + /* If we wanted to preserve the contents of the DRI2 buffer, here we + * would need to do an upsample from singlesample_mt to multisample_mt. + * However, it is unlikely that any app desires that behavior. So we + * invalidate its content for the benefit of avoiding the upsample + * performance penalty. + */ </blockquote><div> Is this function called after every buffer swap, or just on the first draw and after a window resize? If it's called after every buffer swap, I agree with you that the performance penalty of upsampling isn't justified. But then I'm worried about the performance penalty of intel_miptree_create_for_renderbuffer (and especially intel_miptree_alloc_mcs, which it calls--that function spends CPU time clearing the MCS buffer, which seems wasteful to do on every frame). If this function is only called for the first draw and after a resize, then it might be better to go ahead and upsample, just so that the behaviour is more consistent between multisampled and single-sampled visuals. </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"> + + return multisample_mt; + } +} + struct intel_mipmap_tree* intel_miptree_create_for_renderbuffer(struct intel_context *intel, gl_format format, diff --git a/src/mesa/drivers/dri/intel/intel_mipmap_tree.h b/src/mesa/drivers/dri/intel/intel_mipmap_tree.h index e5e89f0..bb3fa50 100644 --- a/src/mesa/drivers/dri/intel/intel_mipmap_tree.h +++ b/src/mesa/drivers/dri/intel/intel_mipmap_tree.h @@ -348,6 +348,12 @@ intel_miptree_create_for_region(struct intel_context *intel, gl_format format, struct intel_region *region); +struct intel_mipmap_tree* +intel_miptree_create_for_dri2_buffer(struct intel_context *intel, + gl_format format, + uint32_t num_samples, + struct intel_region *region); + /** * Create a miptree appropriate as the storage for a non-texture renderbuffer. * The miptree has the following properties: -- 1.7.11.2 </blockquote></div>