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c2bcf20172
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.
47 lines
2.0 KiB
C
47 lines
2.0 KiB
C
/*
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* A trace instance for mangoapp where the kernel's tracefs is closed to the app.
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*
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* Valve's mangoapp (Deck mode's performance overlay) reads the GPU memory total on a Qualcomm
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* display driver (msm_dpu / msm_drm) from the gpu_mem_total event, through a tracefs instance of
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* its own - and aborts when tracefs_instance_create() fails, taking the whole overlay with it.
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* Android mounts tracefs for root and the readtracefs group only, so it always fails here.
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*
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* The real calls run first. Only when they fail is the instance placed in an empty directory of
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* the session's own, where it exists but has no events: the overlay runs, and the one reading it
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* cannot take shows no GPU memory.
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*/
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#define _GNU_SOURCE
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#include <dlfcn.h>
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#include <limits.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/stat.h>
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#define STANDIN_DIR "/tmp/droiddeck-tracefs"
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struct tracefs_instance;
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struct tep_handle;
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struct tracefs_instance *tracefs_instance_create(const char *name) {
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struct tracefs_instance *(*real)(const char *) = dlsym(RTLD_NEXT, "tracefs_instance_create");
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struct tracefs_instance *instance = real ? real(name) : NULL;
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if (instance || !name) return instance;
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struct tracefs_instance *(*alloc)(const char *, const char *) = dlsym(RTLD_NEXT, "tracefs_instance_alloc");
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if (!alloc) return NULL;
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char path[PATH_MAX];
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mkdir(STANDIN_DIR, 0700);
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mkdir(STANDIN_DIR "/instances", 0700);
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snprintf(path, sizeof(path), STANDIN_DIR "/instances/%s", name);
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mkdir(path, 0700);
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return alloc(STANDIN_DIR, name);
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}
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/* The stand-in has no event formats to read, so it gets an empty handle rather than none. */
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struct tep_handle *tracefs_local_events(const char *tracing_dir) {
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struct tep_handle *(*real)(const char *) = dlsym(RTLD_NEXT, "tracefs_local_events");
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struct tep_handle *tep = real ? real(tracing_dir) : NULL;
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if (tep || !tracing_dir || strncmp(tracing_dir, STANDIN_DIR "/", sizeof(STANDIN_DIR))) return tep;
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struct tep_handle *(*tep_alloc)(void) = dlsym(RTLD_DEFAULT, "tep_alloc");
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return tep_alloc ? tep_alloc() : NULL;
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}
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