Driving the null backend blind, using the memory screen-id as the guide, to the
SAME screen the rendered run froze on (screen 4):
guest churn 19 of 8,089,600 bytes in 4 s (0.000%)
Main XThread 0 ms CPU / 4 s, state S, wchan futex_do_wait
log AllocRange unable ... 134217728 bytes; guest throw
Frozen identically with no rasterizer at all.
The flaw is the comparison, not the data. The earlier "control" measured the
null-GPU run while it was still in the MENUS and the lavapipe run AT the freeze,
then reported the difference as a backend effect. The allocations I cited as
proof it had walked through the content load (114 -> 120) were menu-time
allocations. A control needs both arms verified to be in the same state -- and
the memory screen-id built this same session is exactly what makes that
checkable, which I failed to use on the arm that mattered.
Withdrawn: "the freeze requires the rasterizer", "the fault is in the host
rendering path", and the hardware-Vulkan blocker that followed from it. The
rendering question is no longer load-bearing.
Survives: the freeze happens on the first content load after the main menu, on
every route and BOTH GPU backends, with Main XThread futex-blocked at zero CPU
rather than spinning; and four runs froze with three different allocation
outcomes, so the 128 MB refusal is correlated but not necessary.
Also survives and is independently verified: the memory screen-id navigation,
now reproduced on a third run. It is what exposed this error.
Open again: what is Main XThread waiting on? Identify the futex and its holder,
carefully -- gdb perturbs this measurement.
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