Skip to content

intelReadPixels: fallback to CPU mapping in PBO case for Z24S8 attachments

Submitted by Markus Wick

Assigned to Intel 3D Bugs Mailing List

Link to original bug (#106800)

Description

Created attachment 139997 Apitrace dump of citra showing the performance issue

Hi,

calling glReadPixels for the GL_DEPTH24_STENCIL8 attachment and the GL_DEPTH_STENCIL / GL_UNSIGNED_INT_24_8 format seems to stall the GPU, even if a PBO is bound. 92% of my CPU time is spend in intel_miptree_map.

I guess i965 lacks a copy shader for the tiled Z24S8 attachment to the linear TBO buffer.

Tests was done on: Mesa DRI Intel(R) UHD Graphics 620 (Kabylake GT2) and mesa: 4affeba1

An apitrace dump which highlights this issue in the last frames is attached.

Attachment 139997, "Apitrace dump of citra showing the performance issue":
citra-qt.trace

Version: git

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information