[PATCH v2 0/4] ACPI / EC: Fix ECDT and boot_ec support

[PATCH v2 0/4] ACPI / EC: Fix ECDT and boot_ec support

[Lv Zheng]

Linux uses ECDT only in boot stage (before the namespace is fully
initialized), but there are cases reported that Windows allows ECDT to be
used for OSPM runtime, responding EC events by evaluating _Qxx methods
under the device node indicated in the ECDT.

This patchset changes Linux ECDT support to follow Windows behavior and
also fixes related boot_ec support.

v2:
 Rebased on top of recent linux-pm.git/linux-next.
 Addressed 1 comment from Peter Wu.
 Update patch SOBs.

Lv Zheng (4):
  ACPI / EC: Cleanup first_ec/boot_ec code
  ACPI / EC: Fix a memory leakage issue in acpi_ec_add()
  ACPI / EC: Fix a gap that ECDT EC cannot handle EC events
  ACPI / EC: Fix issues related to boot_ec

 drivers/acpi/ec.c       |  240 +++++++++++++++++++++++++++++++++++++----------
 drivers/acpi/internal.h |    1 +
 drivers/acpi/scan.c     |    1 +
 3 files changed, 195 insertions(+), 47 deletions(-)

-- 
1.7.10

[PATCH v2 1/4] ACPI / EC: Cleanup first_ec/boot_ec code

[Lv Zheng]

In order to support full ECDT (driving the ECDT EC after probing the
namespace EC), we need to change our EC device alloc/free algorithm, ensure
not to free old boot EC before qualifying new boot EC.
This patch achieves this by cleaning up first_ec/boot_ec logic:
1. first_ec: used to perform transactions, so it is assigned in new
   acpi_ec_setup() function.
2. boot_ec: used to track early EC device, so it is assigned in new
   acpi_config_boot_ec() function which explictly tells the driver to save
   the EC device as early EC device.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=115021
Reported-and-tested-by: Luya Tshimbalanga <luya@fedoraproject.org>
Tested-by: Jonh Henderson <jw.hendy@gmail.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Cc: Peter Wu <peter@lekensteyn.nl>
---
 drivers/acpi/ec.c |   96 +++++++++++++++++++++++++++++++++++------------------
 1 file changed, 63 insertions(+), 33 deletions(-)

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 1925589..9eab651 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -184,6 +184,7 @@ static void acpi_ec_event_processor(struct work_struct *work);
 
 struct acpi_ec *boot_ec, *first_ec;
 EXPORT_SYMBOL(first_ec);
+static bool boot_ec_is_ecdt = false;
 static struct workqueue_struct *ec_query_wq;
 
 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
@@ -1304,7 +1305,16 @@ acpi_ec_space_handler(u32 function, acpi_physical_address address,
 static acpi_status
 ec_parse_io_ports(struct acpi_resource *resource, void *context);
 
-static struct acpi_ec *make_acpi_ec(void)
+static void acpi_ec_free(struct acpi_ec *ec)
+{
+	if (first_ec == ec)
+		first_ec = NULL;
+	if (boot_ec == ec)
+		boot_ec = NULL;
+	kfree(ec);
+}
+
+static struct acpi_ec *acpi_ec_alloc(void)
 {
 	struct acpi_ec *ec = kzalloc(sizeof(struct acpi_ec), GFP_KERNEL);
 
@@ -1365,6 +1375,11 @@ ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
 	return AE_CTRL_TERMINATE;
 }
 
+/*
+ * Note: This function returns an error code only when the address space
+ *       handler is not installed, which means "not able to handle
+ *       transactions".
+ */
 static int ec_install_handlers(struct acpi_ec *ec)
 {
 	acpi_status status;
@@ -1440,21 +1455,49 @@ static void ec_remove_handlers(struct acpi_ec *ec)
 	}
 }
 
-static struct acpi_ec *acpi_ec_alloc(void)
+static int acpi_ec_setup(struct acpi_ec *ec)
 {
-	struct acpi_ec *ec;
+	int ret;
 
-	/* Check for boot EC */
-	if (boot_ec) {
-		ec = boot_ec;
-		boot_ec = NULL;
-		ec_remove_handlers(ec);
-		if (first_ec == ec)
-			first_ec = NULL;
-	} else {
-		ec = make_acpi_ec();
+	ret = ec_install_handlers(ec);
+	if (ret)
+		return ret;
+
+	/* First EC capable of handling transactions */
+	if (!first_ec) {
+		first_ec = ec;
+		acpi_handle_info(first_ec->handle, "Used as first EC\n");
 	}
-	return ec;
+
+	acpi_handle_info(ec->handle,
+			 "GPE=0x%lx, EC_CMD/EC_SC=0x%lx, EC_DATA=0x%lx\n",
+			 ec->gpe, ec->command_addr, ec->data_addr);
+	return ret;
+}
+
+static int acpi_config_boot_ec(struct acpi_ec *ec, bool is_ecdt)
+{
+	int ret;
+
+	if (boot_ec)
+		ec_remove_handlers(boot_ec);
+
+	/* Unset old boot EC */
+	if (boot_ec != ec)
+		acpi_ec_free(boot_ec);
+
+	ret = acpi_ec_setup(ec);
+	if (ret)
+		return ret;
+
+	/* Set new boot EC */
+	if (!boot_ec) {
+		boot_ec = ec;
+		boot_ec_is_ecdt = is_ecdt;
+		acpi_handle_info(boot_ec->handle, "Used as boot %s EC\n",
+				 is_ecdt ? "ECDT" : "DSDT");
+	}
+	return ret;
 }
 
 static int acpi_ec_add(struct acpi_device *device)
@@ -1470,7 +1513,7 @@ static int acpi_ec_add(struct acpi_device *device)
 		return -ENOMEM;
 	if (ec_parse_device(device->handle, 0, ec, NULL) !=
 		AE_CTRL_TERMINATE) {
-			kfree(ec);
+			acpi_ec_free(ec);
 			return -EINVAL;
 	}
 
@@ -1478,8 +1521,6 @@ static int acpi_ec_add(struct acpi_device *device)
 	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
 			    acpi_ec_register_query_methods, NULL, ec, NULL);
 
-	if (!first_ec)
-		first_ec = ec;
 	device->driver_data = ec;
 
 	ret = !!request_region(ec->data_addr, 1, "EC data");
@@ -1487,10 +1528,7 @@ static int acpi_ec_add(struct acpi_device *device)
 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
 
-	pr_info("GPE = 0x%lx, I/O: command/status = 0x%lx, data = 0x%lx\n",
-			  ec->gpe, ec->command_addr, ec->data_addr);
-
-	ret = ec_install_handlers(ec);
+	ret = acpi_config_boot_ec(ec, false);
 
 	/* Reprobe devices depending on the EC */
 	acpi_walk_dep_device_list(ec->handle);
@@ -1513,9 +1551,7 @@ static int acpi_ec_remove(struct acpi_device *device)
 	release_region(ec->data_addr, 1);
 	release_region(ec->command_addr, 1);
 	device->driver_data = NULL;
-	if (ec == first_ec)
-		first_ec = NULL;
-	kfree(ec);
+	acpi_ec_free(ec);
 	return 0;
 }
 
@@ -1567,13 +1603,10 @@ int __init acpi_ec_dsdt_probe(void)
 		ret = -ENODEV;
 		goto error;
 	}
-	ret = ec_install_handlers(ec);
-
+	ret = acpi_config_boot_ec(ec, false);
 error:
 	if (ret)
-		kfree(ec);
-	else
-		first_ec = boot_ec = ec;
+		acpi_ec_free(ec);
 	return ret;
 }
 
@@ -1671,7 +1704,6 @@ int __init acpi_ec_ecdt_probe(void)
 		goto error;
 	}
 
-	pr_info("EC description table is found, configuring boot EC\n");
 	if (EC_FLAGS_CORRECT_ECDT) {
 		ec->command_addr = ecdt_ptr->data.address;
 		ec->data_addr = ecdt_ptr->control.address;
@@ -1681,12 +1713,10 @@ int __init acpi_ec_ecdt_probe(void)
 	}
 	ec->gpe = ecdt_ptr->gpe;
 	ec->handle = ACPI_ROOT_OBJECT;
-	ret = ec_install_handlers(ec);
+	ret = acpi_config_boot_ec(ec, true);
 error:
 	if (ret)
-		kfree(ec);
-	else
-		first_ec = boot_ec = ec;
+		acpi_ec_free(ec);
 	return ret;
 }
 
-- 
1.7.10

[PATCH v2 2/4] ACPI / EC: Fix a memory leakage issue in acpi_ec_add()

[Lv Zheng]

When the handler installation failed, there was no code to free the
allocated EC device. This patch fixes this memory leakage issue.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=115021
Reported-and-tested-by: Luya Tshimbalanga <luya@fedoraproject.org>
Tested-by: Jonh Henderson <jw.hendy@gmail.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Cc: Peter Wu <peter@lekensteyn.nl>
---
 drivers/acpi/ec.c |   16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 9eab651..50895ff 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -1513,14 +1513,18 @@ static int acpi_ec_add(struct acpi_device *device)
 		return -ENOMEM;
 	if (ec_parse_device(device->handle, 0, ec, NULL) !=
 		AE_CTRL_TERMINATE) {
-			acpi_ec_free(ec);
-			return -EINVAL;
+			ret = -EINVAL;
+			goto err_alloc;
 	}
 
 	/* Find and register all query methods */
 	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
 			    acpi_ec_register_query_methods, NULL, ec, NULL);
 
+	ret = acpi_config_boot_ec(ec, false);
+	if (ret)
+		goto err_query;
+
 	device->driver_data = ec;
 
 	ret = !!request_region(ec->data_addr, 1, "EC data");
@@ -1528,13 +1532,17 @@ static int acpi_ec_add(struct acpi_device *device)
 	ret = !!request_region(ec->command_addr, 1, "EC cmd");
 	WARN(!ret, "Could not request EC cmd io port 0x%lx", ec->command_addr);
 
-	ret = acpi_config_boot_ec(ec, false);
-
 	/* Reprobe devices depending on the EC */
 	acpi_walk_dep_device_list(ec->handle);
 
 	/* EC is fully operational, allow queries */
 	acpi_ec_enable_event(ec);
+	return 0;
+
+err_query:
+	acpi_ec_remove_query_handlers(ec, true, 0);
+err_alloc:
+	acpi_ec_free(ec);
 	return ret;
 }
 
-- 
1.7.10

[PATCH v2 3/4] ACPI / EC: Fix a gap that ECDT EC cannot handle EC events

[Lv Zheng]

It is possible to register _Qxx from namespace and use the ECDT EC to
perform event handling. The reported bug reveals that Windows is using ECDT
in this way in case the namespace EC is not present. This patch facilitates
Linux to support ECDT in this way.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=115021
Reported-and-tested-by: Luya Tshimbalanga <luya@fedoraproject.org>
Tested-by: Jonh Henderson <jw.hendy@gmail.com>
Reviewed-by: Peter Wu <peter@lekensteyn.nl>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Cc: Peter Wu <peter@lekensteyn.nl>
---
 drivers/acpi/ec.c       |  119 ++++++++++++++++++++++++++++++++++++++---------
 drivers/acpi/internal.h |    1 +
 drivers/acpi/scan.c     |    1 +
 3 files changed, 98 insertions(+), 23 deletions(-)

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 50895ff..2ae9194 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -109,6 +109,7 @@ enum {
 	EC_FLAGS_QUERY_GUARDING,	/* Guard for SCI_EVT check */
 	EC_FLAGS_GPE_HANDLER_INSTALLED,	/* GPE handler installed */
 	EC_FLAGS_EC_HANDLER_INSTALLED,	/* OpReg handler installed */
+	EC_FLAGS_EVT_HANDLER_INSTALLED, /* _Qxx handlers installed */
 	EC_FLAGS_STARTED,		/* Driver is started */
 	EC_FLAGS_STOPPED,		/* Driver is stopped */
 	EC_FLAGS_COMMAND_STORM,		/* GPE storms occurred to the
@@ -1380,7 +1381,7 @@ ec_parse_device(acpi_handle handle, u32 Level, void *context, void **retval)
  *       handler is not installed, which means "not able to handle
  *       transactions".
  */
-static int ec_install_handlers(struct acpi_ec *ec)
+static int ec_install_handlers(struct acpi_ec *ec, bool handle_events)
 {
 	acpi_status status;
 
@@ -1409,6 +1410,16 @@ static int ec_install_handlers(struct acpi_ec *ec)
 		set_bit(EC_FLAGS_EC_HANDLER_INSTALLED, &ec->flags);
 	}
 
+	if (!handle_events)
+		return 0;
+
+	if (!test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
+		/* Find and register all query methods */
+		acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
+				    acpi_ec_register_query_methods,
+				    NULL, ec, NULL);
+		set_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
+	}
 	if (!test_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags)) {
 		status = acpi_install_gpe_raw_handler(NULL, ec->gpe,
 					  ACPI_GPE_EDGE_TRIGGERED,
@@ -1419,6 +1430,9 @@ static int ec_install_handlers(struct acpi_ec *ec)
 			if (test_bit(EC_FLAGS_STARTED, &ec->flags) &&
 			    ec->reference_count >= 1)
 				acpi_ec_enable_gpe(ec, true);
+
+			/* EC is fully operational, allow queries */
+			acpi_ec_enable_event(ec);
 		}
 	}
 
@@ -1453,13 +1467,17 @@ static void ec_remove_handlers(struct acpi_ec *ec)
 			pr_err("failed to remove gpe handler\n");
 		clear_bit(EC_FLAGS_GPE_HANDLER_INSTALLED, &ec->flags);
 	}
+	if (test_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags)) {
+		acpi_ec_remove_query_handlers(ec, true, 0);
+		clear_bit(EC_FLAGS_EVT_HANDLER_INSTALLED, &ec->flags);
+	}
 }
 
-static int acpi_ec_setup(struct acpi_ec *ec)
+static int acpi_ec_setup(struct acpi_ec *ec, bool handle_events)
 {
 	int ret;
 
-	ret = ec_install_handlers(ec);
+	ret = ec_install_handlers(ec, handle_events);
 	if (ret)
 		return ret;
 
@@ -1475,18 +1493,33 @@ static int acpi_ec_setup(struct acpi_ec *ec)
 	return ret;
 }
 
-static int acpi_config_boot_ec(struct acpi_ec *ec, bool is_ecdt)
+static int acpi_config_boot_ec(struct acpi_ec *ec, acpi_handle handle,
+			       bool handle_events, bool is_ecdt)
 {
 	int ret;
 
-	if (boot_ec)
+	/*
+	 * Changing the ACPI handle results in a re-configuration of the
+	 * boot EC. And if it happens after the namespace initialization,
+	 * it causes _REG evaluations.
+	 */
+	if (boot_ec && boot_ec->handle != handle)
 		ec_remove_handlers(boot_ec);
 
 	/* Unset old boot EC */
 	if (boot_ec != ec)
 		acpi_ec_free(boot_ec);
 
-	ret = acpi_ec_setup(ec);
+	/*
+	 * ECDT device creation is split into acpi_ec_ecdt_probe() and
+	 * acpi_ec_ecdt_start(). This function takes care of completing the
+	 * ECDT parsing logic as the handle update should be performed
+	 * between the installation/uninstallation of the handlers.
+	 */
+	if (ec->handle != handle)
+		ec->handle = handle;
+
+	ret = acpi_ec_setup(ec, handle_events);
 	if (ret)
 		return ret;
 
@@ -1494,9 +1527,12 @@ static int acpi_config_boot_ec(struct acpi_ec *ec, bool is_ecdt)
 	if (!boot_ec) {
 		boot_ec = ec;
 		boot_ec_is_ecdt = is_ecdt;
-		acpi_handle_info(boot_ec->handle, "Used as boot %s EC\n",
-				 is_ecdt ? "ECDT" : "DSDT");
 	}
+
+	acpi_handle_info(boot_ec->handle,
+			 "Used as boot %s EC to handle transactions%s\n",
+			 is_ecdt ? "ECDT" : "DSDT",
+			 handle_events ? " and events" : "");
 	return ret;
 }
 
@@ -1517,11 +1553,7 @@ static int acpi_ec_add(struct acpi_device *device)
 			goto err_alloc;
 	}
 
-	/* Find and register all query methods */
-	acpi_walk_namespace(ACPI_TYPE_METHOD, ec->handle, 1,
-			    acpi_ec_register_query_methods, NULL, ec, NULL);
-
-	ret = acpi_config_boot_ec(ec, false);
+	ret = acpi_config_boot_ec(ec, device->handle, true, false);
 	if (ret)
 		goto err_query;
 
@@ -1534,9 +1566,6 @@ static int acpi_ec_add(struct acpi_device *device)
 
 	/* Reprobe devices depending on the EC */
 	acpi_walk_dep_device_list(ec->handle);
-
-	/* EC is fully operational, allow queries */
-	acpi_ec_enable_event(ec);
 	return 0;
 
 err_query:
@@ -1555,7 +1584,6 @@ static int acpi_ec_remove(struct acpi_device *device)
 
 	ec = acpi_driver_data(device);
 	ec_remove_handlers(ec);
-	acpi_ec_remove_query_handlers(ec, true, 0);
 	release_region(ec->data_addr, 1);
 	release_region(ec->command_addr, 1);
 	device->driver_data = NULL;
@@ -1601,9 +1629,8 @@ int __init acpi_ec_dsdt_probe(void)
 	if (!ec)
 		return -ENOMEM;
 	/*
-	 * Finding EC from DSDT if there is no ECDT EC available. When this
-	 * function is invoked, ACPI tables have been fully loaded, we can
-	 * walk namespace now.
+	 * At this point, the namespace is initialized, so start to find
+	 * the namespace objects.
 	 */
 	status = acpi_get_devices(ec_device_ids[0].id,
 				  ec_parse_device, ec, NULL);
@@ -1611,13 +1638,55 @@ int __init acpi_ec_dsdt_probe(void)
 		ret = -ENODEV;
 		goto error;
 	}
-	ret = acpi_config_boot_ec(ec, false);
+	/*
+	 * When the DSDT EC is available, always re-configure boot EC to
+	 * have _REG evaluated. _REG can only be evaluated after the
+	 * namespace initialization.
+	 * At this point, the GPE is not fully initialized, so do not to
+	 * handle the events.
+	 */
+	ret = acpi_config_boot_ec(ec, ec->handle, false, false);
 error:
 	if (ret)
 		acpi_ec_free(ec);
 	return ret;
 }
 
+/*
+ * If the DSDT EC is not functioning, we still need to prepare a fully
+ * functioning ECDT EC first in order to handle the events.
+ * https://bugzilla.kernel.org/show_bug.cgi?id=115021
+ */
+int __init acpi_ec_ecdt_start(void)
+{
+	struct acpi_table_ecdt *ecdt_ptr;
+	acpi_status status;
+	acpi_handle handle;
+
+	if (!boot_ec)
+		return -ENODEV;
+	/*
+	 * The DSDT EC should have already been started in
+	 * acpi_ec_add().
+	 */
+	if (!boot_ec_is_ecdt)
+		return -ENODEV;
+
+	status = acpi_get_table(ACPI_SIG_ECDT, 1,
+				(struct acpi_table_header **)&ecdt_ptr);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+
+	/*
+	 * At this point, the namespace and the GPE is initialized, so
+	 * start to find the namespace objects and handle the events.
+	 */
+	status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
+	if (ACPI_FAILURE(status))
+		return -ENODEV;
+	return acpi_config_boot_ec(boot_ec, handle, true, true);
+}
+
 #if 0
 /*
  * Some EC firmware variations refuses to respond QR_EC when SCI_EVT is not
@@ -1720,8 +1789,12 @@ int __init acpi_ec_ecdt_probe(void)
 		ec->data_addr = ecdt_ptr->data.address;
 	}
 	ec->gpe = ecdt_ptr->gpe;
-	ec->handle = ACPI_ROOT_OBJECT;
-	ret = acpi_config_boot_ec(ec, true);
+
+	/*
+	 * At this point, the namespace is not initialized, so do not find
+	 * the namespace objects, or handle the events.
+	 */
+	ret = acpi_config_boot_ec(ec, ACPI_ROOT_OBJECT, false, true);
 error:
 	if (ret)
 		acpi_ec_free(ec);
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h
index 358b012..3797155 100644
--- a/drivers/acpi/internal.h
+++ b/drivers/acpi/internal.h
@@ -186,6 +186,7 @@ typedef int (*acpi_ec_query_func) (void *data);
 int acpi_ec_init(void);
 int acpi_ec_ecdt_probe(void);
 int acpi_ec_dsdt_probe(void);
+int acpi_ec_ecdt_start(void);
 void acpi_ec_block_transactions(void);
 void acpi_ec_unblock_transactions(void);
 int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c
index e878fc7..f8f9f4e 100644
--- a/drivers/acpi/scan.c
+++ b/drivers/acpi/scan.c
@@ -2044,6 +2044,7 @@ int __init acpi_scan_init(void)
 	}
 
 	acpi_update_all_gpes();
+	acpi_ec_ecdt_start();
 
 	acpi_scan_initialized = true;
 
-- 
1.7.10

[PATCH v2 4/4] ACPI / EC: Fix issues related to boot_ec

[Lv Zheng]

There are issues related to the boot_ec:
1. If acpi_ec_remove() is invoked, boot_ec will also be freed, this is not
   expected as the boot_ec could be enumerated via ECDT.
2. Address space handler installation/unstallation lead to unexpected _REG
   evaluations.
This patch adds acpi_is_boot_ec() check to be used to fix the above issues.
However, since acpi_ec_remove() actually won't be invoked, this patch
doesn't handle the reference counting of "struct acpi_ec", it only ensures
the correctness of the boot_ec destruction during the boot.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=153511
Reported-and-tested-by: Jonh Henderson <jw.hendy@gmail.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Cc: Peter Wu <peter@lekensteyn.nl>
---
 drivers/acpi/ec.c |   63 +++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 49 insertions(+), 14 deletions(-)

diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index 2ae9194..6805310 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -1536,6 +1536,37 @@ static int acpi_config_boot_ec(struct acpi_ec *ec, acpi_handle handle,
 	return ret;
 }
 
+static bool acpi_ec_ecdt_get_handle(acpi_handle *phandle)
+{
+	struct acpi_table_ecdt *ecdt_ptr;
+	acpi_status status;
+	acpi_handle handle;
+
+	status = acpi_get_table(ACPI_SIG_ECDT, 1,
+				(struct acpi_table_header **)&ecdt_ptr);
+	if (ACPI_FAILURE(status))
+		return false;
+
+	status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
+	if (ACPI_FAILURE(status))
+		return false;
+
+	*phandle = handle;
+	return true;
+}
+
+static bool acpi_is_boot_ec(struct acpi_ec *ec)
+{
+	if (!boot_ec)
+		return false;
+	if (ec->handle == boot_ec->handle &&
+	    ec->gpe == boot_ec->gpe &&
+	    ec->command_addr == boot_ec->command_addr &&
+	    ec->data_addr == boot_ec->data_addr)
+		return true;
+	return false;
+}
+
 static int acpi_ec_add(struct acpi_device *device)
 {
 	struct acpi_ec *ec = NULL;
@@ -1553,7 +1584,14 @@ static int acpi_ec_add(struct acpi_device *device)
 			goto err_alloc;
 	}
 
-	ret = acpi_config_boot_ec(ec, device->handle, true, false);
+	if (acpi_is_boot_ec(ec)) {
+		boot_ec_is_ecdt = false;
+		acpi_handle_debug(ec->handle, "duplicated.\n");
+		acpi_ec_free(ec);
+		ec = boot_ec;
+		ret = acpi_config_boot_ec(ec, ec->handle, true, false);
+	} else
+		ret = acpi_ec_setup(ec, true);
 	if (ret)
 		goto err_query;
 
@@ -1566,12 +1604,15 @@ static int acpi_ec_add(struct acpi_device *device)
 
 	/* Reprobe devices depending on the EC */
 	acpi_walk_dep_device_list(ec->handle);
+	acpi_handle_debug(ec->handle, "enumerated.\n");
 	return 0;
 
 err_query:
-	acpi_ec_remove_query_handlers(ec, true, 0);
+	if (ec != boot_ec)
+		acpi_ec_remove_query_handlers(ec, true, 0);
 err_alloc:
-	acpi_ec_free(ec);
+	if (ec != boot_ec)
+		acpi_ec_free(ec);
 	return ret;
 }
 
@@ -1583,11 +1624,13 @@ static int acpi_ec_remove(struct acpi_device *device)
 		return -EINVAL;
 
 	ec = acpi_driver_data(device);
-	ec_remove_handlers(ec);
 	release_region(ec->data_addr, 1);
 	release_region(ec->command_addr, 1);
 	device->driver_data = NULL;
-	acpi_ec_free(ec);
+	if (ec != boot_ec) {
+		ec_remove_handlers(ec);
+		acpi_ec_free(ec);
+	}
 	return 0;
 }
 
@@ -1659,8 +1702,6 @@ error:
  */
 int __init acpi_ec_ecdt_start(void)
 {
-	struct acpi_table_ecdt *ecdt_ptr;
-	acpi_status status;
 	acpi_handle handle;
 
 	if (!boot_ec)
@@ -1672,17 +1713,11 @@ int __init acpi_ec_ecdt_start(void)
 	if (!boot_ec_is_ecdt)
 		return -ENODEV;
 
-	status = acpi_get_table(ACPI_SIG_ECDT, 1,
-				(struct acpi_table_header **)&ecdt_ptr);
-	if (ACPI_FAILURE(status))
-		return -ENODEV;
-
 	/*
 	 * At this point, the namespace and the GPE is initialized, so
 	 * start to find the namespace objects and handle the events.
 	 */
-	status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
-	if (ACPI_FAILURE(status))
+	if (!acpi_ec_ecdt_get_handle(&handle))
 		return -ENODEV;
 	return acpi_config_boot_ec(boot_ec, handle, true, true);
 }
-- 
1.7.10

Re: [PATCH v2 0/4] ACPI / EC: Fix ECDT and boot_ec support

[Rafael J. Wysocki]

On Wednesday, September 07, 2016 04:49:59 PM Lv Zheng wrote:
> Linux uses ECDT only in boot stage (before the namespace is fully
> initialized), but there are cases reported that Windows allows ECDT to be
> used for OSPM runtime, responding EC events by evaluating _Qxx methods
> under the device node indicated in the ECDT.
> 
> This patchset changes Linux ECDT support to follow Windows behavior and
> also fixes related boot_ec support.
> 
> v2:
>  Rebased on top of recent linux-pm.git/linux-next.
>  Addressed 1 comment from Peter Wu.
>  Update patch SOBs.
> 
> Lv Zheng (4):
>   ACPI / EC: Cleanup first_ec/boot_ec code
>   ACPI / EC: Fix a memory leakage issue in acpi_ec_add()
>   ACPI / EC: Fix a gap that ECDT EC cannot handle EC events
>   ACPI / EC: Fix issues related to boot_ec
> 
>  drivers/acpi/ec.c       |  240 +++++++++++++++++++++++++++++++++++++----------
>  drivers/acpi/internal.h |    1 +
>  drivers/acpi/scan.c     |    1 +
>  3 files changed, 195 insertions(+), 47 deletions(-)

Whole series applied.

Thanks,
Rafael