mangoapp's VRAM figure on a Qualcomm driver comes only from the gpu_mem_total
trace event. The tracefs stand-in's event list now declares that event as
Android kernels do, and reading the stand-in's events answers with one
record carrying the total KGSL reports in /sys/class/kgsl/kgsl/page_alloc,
which every Adreno under Android has and the app can read.
Three things kept Valve's mangoapp from drawing the overlay in a session:
- GLFW 3.4 takes XDG_SESSION_TYPE=wayland with WAYLAND_DISPLAY set as
Wayland-only, and mangoapp needs gamescope's X server; the wrapper sets
XDG_SESSION_TYPE=x11.
- On a Qualcomm display driver it opens a tracefs instance for the GPU memory
total and aborts when that fails, which it always does for an Android app.
The session preload now places the instance in an empty directory of its own
when the real one cannot be made.
- gamescope sends it each frame's timings through a System V message queue,
and Android kernels have no System V IPC. sysv.c now emulates the queue
operations gamescope and mangoapp use, beside its semaphores and shared
memory.
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