From 374a95aca7455fdbee0531bf2d546829e5c56569 Mon Sep 17 00:00:00 2001
From: Red Bear OS <build@redbearos.org>
Date: Fri, 24 Jul 2026 01:59:26 +0900
Subject: [PATCH] acpid: gate general GPE _Lxx/_Exx dispatch behind
 REDBEAR_ACPI_GPE_DISPATCH

The general GPE dispatch runs on acpid's single main-loop thread, which
also serves /scheme/acpi. A blocking _Lxx/_Exx AML method (e.g. spinning
on a PCI/EC condition that never becomes true) freezes the scheme and
deadlocks every ACPI-reading daemon and therefore the whole boot. Linux
avoids this with a dedicated kacpid thread. Until Red Bear has one, gate
the general dispatch behind REDBEAR_ACPI_GPE_DISPATCH=1 (default OFF);
EC + PM1 fixed events stay always-on (bounded and proven).
---
 drivers/acpid/src/power_events.rs | 42 +++++++++++++++++--------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/drivers/acpid/src/power_events.rs b/drivers/acpid/src/power_events.rs
index 08d8ea5361..6054f9ea0f 100644
--- a/drivers/acpid/src/power_events.rs
+++ b/drivers/acpid/src/power_events.rs
@@ -244,26 +244,30 @@ pub fn handle_sci(context: &AcpiContext) -> Vec<PowerEvent> {
         }
     }
 
-    // General GPE dispatch (evgpe.c acpi_ev_gpe_detect): non-EC enabled+active
-    // GPEs get \_GPE._Lxx (level, tried first) or \_GPE._Exx (edge) evaluated.
-    let ec_gpe = context.ec_device.read().clone().map(|(_, g)| g);
-    for gpe in blocks.enabled_active_gpes() {
-        if Some(gpe) == ec_gpe {
-            continue;
+    // General GPE dispatch (evgpe.c acpi_ev_gpe_detect). It runs on acpid's
+    // main-loop thread, which also serves /scheme/acpi — a blocking _Lxx/_Exx
+    // method would freeze the scheme and deadlock the boot. Opt-in via
+    // REDBEAR_ACPI_GPE_DISPATCH=1, default OFF (EC + PM1 stay always-on).
+    if std::env::var_os("REDBEAR_ACPI_GPE_DISPATCH").is_some() {
+        let ec_gpe = context.ec_device.read().clone().map(|(_, g)| g);
+        for gpe in blocks.enabled_active_gpes() {
+            if Some(gpe) == ec_gpe {
+                continue;
+            }
+            let level = format!("\\_GPE._L{gpe:02X}");
+            let edge = format!("\\_GPE._E{gpe:02X}");
+            let handled = context.evaluate_acpi_method(&level, "", &[]).is_ok()
+                || context.evaluate_acpi_method(&edge, "", &[]).is_ok();
+            if handled {
+                log::info!("acpid: GPE {:#04x} dispatched to AML control method", gpe);
+            } else {
+                log::debug!(
+                    "acpid: GPE {:#04x} active but no _L{gpe:02X}/_E{gpe:02X} method",
+                    gpe
+                );
+            }
+            blocks.clear_gpe(gpe);
         }
-        let level = format!("\\_GPE._L{gpe:02X}");
-        let edge = format!("\\_GPE._E{gpe:02X}");
-        let handled = context.evaluate_acpi_method(&level, "", &[]).is_ok()
-            || context.evaluate_acpi_method(&edge, "", &[]).is_ok();
-        if handled {
-            log::info!("acpid: GPE {:#04x} dispatched to AML control method", gpe);
-        } else {
-            log::debug!(
-                "acpid: GPE {:#04x} active but no _L{gpe:02X}/_E{gpe:02X} method",
-                gpe
-            );
-        }
-        blocks.clear_gpe(gpe);
     }
 
     // Drain AML notifications (from _Qxx methods and any other Notify).