linux-kernel - [PATCH 2/3] ACPICA: Make it possible to enable runtime GPEs earlier

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Message-ID: <51836747.M49Hy56X72@aspire.rjw.lan>
Date:   Thu, 10 Aug 2017 00:31:58 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux ACPI <linux-acpi@...r.kernel.org>
Cc:     Mika Westerberg <mika.westerberg@...ux.intel.com>,
        Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
        Linux PCI <linux-pci@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Lv Zheng <lv.zheng@...el.com>,
        Bob Moore <robert.moore@...el.com>
Subject: [PATCH 2/3] ACPICA: Make it possible to enable runtime GPEs earlier

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Runtime GPEs have corresponding _Lxx/_Exx methods and are enabled
automatically during the initialization of the ACPI subsystem through
acpi_update_all_gpes() with the assumption that acpi_setup_gpe_for_wake()
will be called in advance for all of the GPEs pointed to by _PRW
objects in the namespace that may be affected by acpi_update_all_gpes().
That is, acpi_ev_initialize_gpe_block() can only be called for a GPE
block after acpi_setup_gpe_for_wake() has been called for all of the
_PRW (wakeup) GPEs in it.

The platform firmware on some systems, however, expects GPEs to be
enabled before the enumeration of devices which is when
acpi_setup_gpe_for_wake() is called and that goes against the above
assumption.

For this reason, introduce a new flag to be set by
acpi_ev_initialize_gpe_block() when automatically enabling a GPE
to indicate to acpi_setup_gpe_for_wake() that it needs to drop the
reference to the GPE coming from acpi_ev_initialize_gpe_block()
and modify acpi_setup_gpe_for_wake() accordingly.  These changes
allow acpi_setup_gpe_for_wake() and acpi_ev_initialize_gpe_block()
to be invoked in any order.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/acpi/acpica/evgpeblk.c |    2 ++
 drivers/acpi/acpica/evxfgpe.c  |    8 ++++++++
 include/acpi/actypes.h         |    3 ++-
 3 files changed, 12 insertions(+), 1 deletion(-)

Index: linux-pm/drivers/acpi/acpica/evgpeblk.c
===================================================================
--- linux-pm.orig/drivers/acpi/acpica/evgpeblk.c
+++ linux-pm/drivers/acpi/acpica/evgpeblk.c
@@ -496,6 +496,8 @@ acpi_ev_initialize_gpe_block(struct acpi
 				continue;
 			}
 
+			gpe_event_info->flags |= ACPI_GPE_AUTO_ENABLED;
+
 			if (event_status & ACPI_EVENT_FLAG_STATUS_SET) {
 				ACPI_INFO(("GPE 0x%02X active on init",
 					   gpe_number));
Index: linux-pm/include/acpi/actypes.h
===================================================================
--- linux-pm.orig/include/acpi/actypes.h
+++ linux-pm/include/acpi/actypes.h
@@ -783,7 +783,7 @@ typedef u32 acpi_event_status;
  *   |  | | |  +-- Type of dispatch:to method, handler, notify, or none
  *   |  | | +----- Interrupt type: edge or level triggered
  *   |  | +------- Is a Wake GPE
- *   |  +--------- Is GPE masked by the software GPE masking mechanism
+ *   |  +--------- Has been enabled automatically at init time
  *   +------------ <Reserved>
  */
 #define ACPI_GPE_DISPATCH_NONE          (u8) 0x00
@@ -799,6 +799,7 @@ typedef u32 acpi_event_status;
 #define ACPI_GPE_XRUPT_TYPE_MASK        (u8) 0x08
 
 #define ACPI_GPE_CAN_WAKE               (u8) 0x10
+#define ACPI_GPE_AUTO_ENABLED           (u8) 0x20
 
 /*
  * Flags for GPE and Lock interfaces
Index: linux-pm/drivers/acpi/acpica/evxfgpe.c
===================================================================
--- linux-pm.orig/drivers/acpi/acpica/evxfgpe.c
+++ linux-pm/drivers/acpi/acpica/evxfgpe.c
@@ -435,6 +435,14 @@ acpi_setup_gpe_for_wake(acpi_handle wake
 		 */
 		gpe_event_info->flags =
 		    (ACPI_GPE_DISPATCH_NOTIFY | ACPI_GPE_LEVEL_TRIGGERED);
+	} else if (gpe_event_info->flags & ACPI_GPE_AUTO_ENABLED) {
+		/*
+		 * A reference to this GPE has been added during the GPE block
+		 * initialization, so drop it now to prevent the GPE from being
+		 * permanently enabled and clear its ACPI_GPE_AUTO_ENABLED flag.
+		 */
+		(void)acpi_ev_remove_gpe_reference(gpe_event_info);
+		gpe_event_info->flags &= ~ACPI_GPE_AUTO_ENABLED;
 	}
 
 	/*