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fix: make ACPI shutdown compliant with spec

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This commit is contained in:
Daniel Hammer
2026-03-06 23:44:46 +01:00
parent b560712ecf
commit 8c5c259f5d
1 changed files with 24 additions and 7 deletions
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kernel/src/ACPI/AcpiShutdown.cpp
+23 -6
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@@ -18,6 +18,7 @@ namespace Hal {
namespace AcpiShutdown {
static constexpr uint16_t SLP_EN = 1 << 13;
static constexpr uint16_t SLP_TYP_MASK = 0x1C00; // bits 10-12
static bool g_available = false;
static uint32_t g_pm1aControlBlock = 0;
@@ -60,16 +61,32 @@ namespace Hal {
KernelLogStream(INFO, "ACPI") << "Performing ACPI S5 shutdown...";
// Write SLP_TYPa | SLP_EN to PM1a control register
Io::Out16((g_slpTypA << 10) | SLP_EN, (uint16_t)g_pm1aControlBlock);
asm volatile("cli");
// Phase 1: Write SLP_TYP to PM1x_CNT without SLP_EN,
// preserving existing register bits
uint16_t pm1a = Io::In16((uint16_t)g_pm1aControlBlock);
pm1a = (pm1a & ~SLP_TYP_MASK) | (g_slpTypA << 10);
Io::Out16(pm1a, (uint16_t)g_pm1aControlBlock);
// If PM1b exists, write to it as well
if (g_pm1bControlBlock != 0) {
Io::Out16((g_slpTypB << 10) | SLP_EN, (uint16_t)g_pm1bControlBlock);
uint16_t pm1b = Io::In16((uint16_t)g_pm1bControlBlock);
pm1b = (pm1b & ~SLP_TYP_MASK) | (g_slpTypB << 10);
Io::Out16(pm1b, (uint16_t)g_pm1bControlBlock);
}
// If we're still here, the shutdown didn't work immediately.
// Halt and wait for the hardware to power off.
// Flush all caches before entering sleep state
asm volatile("wbinvd");
// Phase 2: Assert SLP_EN to trigger the transition
Io::Out16(pm1a | SLP_EN, (uint16_t)g_pm1aControlBlock);
if (g_pm1bControlBlock != 0) {
uint16_t pm1b = Io::In16((uint16_t)g_pm1bControlBlock);
Io::Out16(pm1b | SLP_EN, (uint16_t)g_pm1bControlBlock);
}
// Halt and wait for the hardware to power off
for (;;) {
asm volatile("hlt");
}