Details
P3: Somewhat important Description
On Ubuntu 16.04 with the Intel GPU 945GSE (i915) Qt Quick applications are very slow and use a lot of CPU.
I tested it with my own Qt Quick application and as a refernce with the samegame example.
Here some debug output:
$> QSG_INFO=1 ./samegame qt.scenegraph.general: QSG: basic render loop qt.scenegraph.general: Using sg animation driver qt.scenegraph.general: texture atlas dimensions: 512x512 qt.scenegraph.general: R/G/B/A Buffers: 8 8 8 0 qt.scenegraph.general: Depth Buffer: 24 qt.scenegraph.general: Stencil Buffer: 8 qt.scenegraph.general: Samples: -1 qt.scenegraph.general: GL_VENDOR: Intel Open Source Technology Center qt.scenegraph.general: GL_RENDERER: Mesa DRI Intel(R) 945GME x86/MMX/SSE2 qt.scenegraph.general: GL_VERSION: 1.4 Mesa 17.4.0-devel
The samegame uses the particles and as soon these are triggered, the balls disappear very slowly and the CPU is used 100%.
If I start the samegame with INTEL_DEBUG=perf I get the following messages:
$> INTEL_DEBUG=perf ./samegame .... ENTER FALLBACK 10000: Program LEAVE FALLBACK Program i915_program_error: Exceeded max nr indirect texture lookups (6 out of 4) ...
With the perf or oprofile tool I see that the most CPU time is consumed by i915_dri.so.
Is there any workaround or is this a known issue with this Intel GPU?
This bug report seems to be related to my issue: https://bugs.freedesktop.org/show_bug.cgi?id=87478