From d84e4ac55e1dec7e1ce3d8ad8b9c0db9682d48eb Mon Sep 17 00:00:00 2001 From: Arthur Hanson Rasmusson Date: Wed, 21 Oct 2026 06:49:44 -0400 Subject: sema: r408 acquire-wait gate defaults ON (the r408 streams2d readback race) + explicit param desc With the gate off (the mission cycle recipe omitted sema_wait_gate=1), the c2 readback's C56F ACQ_CIRC_GEQ pay=4 ran at 106617.279 with cur=2 - before the c2-add launch was even submitted (106617.411) - and read the not-yet-produced buffer (all zeros). With the gate on the same readback holds until the scale channel's progress counter reaches 4 (sema-wait: hold ... cur=2 waited_ms=353 -> pass ... cur=4) and the ordering is correct. The holds are bounded (sema_wait_hold_ms, default 4000) and fail open loudly, so the pre-r336 pass-through remains available with sema_wait_gate=0 for an A/B. --- kernel/main.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/main.c') diff --git a/kernel/main.c b/kernel/main.c index d2a44d6..0110372 100644 --- a/kernel/main.c +++ b/kernel/main.c @@ -2829,6 +2829,7 @@ MODULE_PARM_DESC(sema_pool_hold_fresh, "apply pool releases at fresh-pin time in */ module_param_named(sema_copy_dst_pin_guard, gsp_sema_copy_dst_pin_guard, bool, 0644); module_param_named(sema_wait_gate, gsp_sema_wait_gate, bool, 0644); +MODULE_PARM_DESC(sema_wait_gate, "honor C56F host-semaphore acquires before running a ring entry's work (default 1 since r408; 0 restores pass-through)"); module_param_named(sema_wait_hold_ms, gsp_sema_wait_hold_ms, uint, 0644); MODULE_PARM_DESC(sema_wait_hold_ms, "bounded acquire-wait hold before fail-open, ms (r401, default 4000; must exceed the emulated launch latency)"); MODULE_PARM_DESC(sema_copy_dst_pin_guard, "hold device-dst copies without a pin-resolved translation (default 1)"); -- cgit v1.2.3