From 95099d4622f8cb224d94e314c7a8e0df60b13f87 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Sat, 09 Dec 2023 08:38:01 +0000
Subject: [PATCH] enable docker ppp

---
 kernel/drivers/acpi/reboot.c |   51 ++++++++++++++++++++++++++++++++++++++-------------
 1 files changed, 38 insertions(+), 13 deletions(-)

diff --git a/kernel/drivers/acpi/reboot.c b/kernel/drivers/acpi/reboot.c
index 6fa9c2a..2a61f88 100644
--- a/kernel/drivers/acpi/reboot.c
+++ b/kernel/drivers/acpi/reboot.c
@@ -3,12 +3,37 @@
 #include <linux/pci.h>
 #include <linux/acpi.h>
 #include <acpi/reboot.h>
+#include <linux/delay.h>
+
+#ifdef CONFIG_PCI
+static void acpi_pci_reboot(struct acpi_generic_address *rr, u8 reset_value)
+{
+	unsigned int devfn;
+	struct pci_bus *bus0;
+
+	/* The reset register can only live on bus 0. */
+	bus0 = pci_find_bus(0, 0);
+	if (!bus0)
+		return;
+	/* Form PCI device/function pair. */
+	devfn = PCI_DEVFN((rr->address >> 32) & 0xffff,
+			  (rr->address >> 16) & 0xffff);
+	pr_debug("Resetting with ACPI PCI RESET_REG.\n");
+	/* Write the value that resets us. */
+	pci_bus_write_config_byte(bus0, devfn,
+			(rr->address & 0xffff), reset_value);
+}
+#else
+static inline void acpi_pci_reboot(struct acpi_generic_address *rr,
+				   u8 reset_value)
+{
+	pr_warn_once("PCI configuration space access is not supported\n");
+}
+#endif
 
 void acpi_reboot(void)
 {
 	struct acpi_generic_address *rr;
-	struct pci_bus *bus0;
-	unsigned int devfn;
 	u8 reset_value;
 
 	if (acpi_disabled)
@@ -33,17 +58,7 @@
 	 * on a device on bus 0. */
 	switch (rr->space_id) {
 	case ACPI_ADR_SPACE_PCI_CONFIG:
-		/* The reset register can only live on bus 0. */
-		bus0 = pci_find_bus(0, 0);
-		if (!bus0)
-			return;
-		/* Form PCI device/function pair. */
-		devfn = PCI_DEVFN((rr->address >> 32) & 0xffff,
-				  (rr->address >> 16) & 0xffff);
-		printk(KERN_DEBUG "Resetting with ACPI PCI RESET_REG.\n");
-		/* Write the value that resets us. */
-		pci_bus_write_config_byte(bus0, devfn,
-				(rr->address & 0xffff), reset_value);
+		acpi_pci_reboot(rr, reset_value);
 		break;
 
 	case ACPI_ADR_SPACE_SYSTEM_MEMORY:
@@ -52,4 +67,14 @@
 		acpi_reset();
 		break;
 	}
+
+	/*
+	 * Some platforms do not shut down immediately after writing to the
+	 * ACPI reset register, and this results in racing with the
+	 * subsequent reboot mechanism.
+	 *
+	 * The 15ms delay has been found to be long enough for the system
+	 * to reboot on the affected platforms.
+	 */
+	mdelay(15);
 }

--
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