From fffec0f04dfcc63bef39eb0441cfad7b584da484 Mon Sep 17 00:00:00 2001 From: salmonik Date: Sat, 1 Aug 2026 23:44:41 +0200 Subject: rsnix v0.5.3: fix real-hardware scroll wedge — per-word display push MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The real-hardware crash (2 lines of white + freeze, no CPU exception even with the 0.5.2 fault dumps) pointed away from a fault and at a stall: the scroll's full-frame push used one 1.92 MB rep-movsb to the framebuffer. On QEMU the framebuffer is RAM, so it flies; on a real GPU the framebuffer is uncached MMIO and the CPU's fast-string burst path can stall forever — the shell wedges mid-instruction, the cursor task's own writes wedge too, no exception fires (MMIO writes don't fault), and the screen shows the torn partial push (the white bands). The boot-time clear() always worked on the same hardware and uses per-word volatile stores, so the scroll push now uses the identical pattern: shadow reads (cached RAM, cheap) + individually-posted display stores. Interruptible between stores, never a bulk burst, and functionally identical on QEMU (all 5 suites re-pass). Also converts the no-shadow fallback shift to the same per-word pattern. CONTEXT.md updated (scroll-cost note + versioning). --- rsnix/src/sched.rs | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'rsnix/src/sched.rs') diff --git a/rsnix/src/sched.rs b/rsnix/src/sched.rs index cfce58f..f48e210 100644 --- a/rsnix/src/sched.rs +++ b/rsnix/src/sched.rs @@ -282,7 +282,11 @@ pub fn spawn(entry: fn(), name: &str) -> Option { }; let ok = spawn_at(id, entry, name); unlock(); - if ok { Some(id) } else { None } + if ok { + Some(id) + } else { + None + } } unsafe fn reap(id: usize) { -- cgit v1.2.3