hello, i've just recently subscribed to the ML because i have an issue with Qt app in an embedded environment.
i'm just trying the analogclock sample on an embedded ARM board (Allwinner A20 SOM EVB for precisione sake) and i find it's hogging the CPU. the SW stack is based on buildroot 2017.08 environment that provides a lib qt5.9.1 / sw rasterizer on the basic DRM/KMS driver running on mainline 4.15rcx kernel i run callgrind for profiling , but i can't figure out from the resulting data what's going on.. i.e. kcachegrind provides beautiful graphs and maps.. but i suppose it takes some time to understand how the CPU time is spent i'm wondering if the issue is related to the underlying DRM/KMS is still missing some hooks/features for the Qt stack be happy.. i set the env var "GALLIUM_HUD="cpu,fps" but the fps stays 0 (and CPU is stuck on 50%, i suppose because it means one core of the two is 100% hogged) see this shot: https://drive.google.com/open?id=1vitoJrWyYO_WE5-60XlRHahmVrzGnv2m eventually the callgrind profiling data are here: https://drive.google.com/file/d/1VMkD8sNwZBsH5dRo8EJzz6Vi3_E5M0XT to make issue more puzzling, if i define "QT_QPA_PLATFORM='linuxfb:fb=/dev/fb0'", as the kernel has also "fbdev emulation", the clock is running fine with 0% of CPU usage.. i suppose because it takes another code path.. any suggestion where to move forward for debugging? andrea
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