linux-kernel - [PATCH 6/7 v2] auto bind the memory device which is hotpluged before the driver is loaded

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Date:	Wed, 11 Jul 2012 15:50:17 +0800
From:	Wen Congyang <wency@...fujitsu.com>
To:	lenb@...nel.org, linux-acpi@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:	Yasuaki ISIMATU <isimatu.yasuaki@...fujitsu.com>,
	David Rientjes <rientjes@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Subject: [PATCH 6/7 v2] auto bind the memory device which is hotpluged before
 the driver is loaded

If the memory device is hotpluged before the driver is loaded, the
user cannot see this device under the directory /sys/bus/acpi/devices/,
and the user cannot bind it by hand after the driver is loaded.
This patch introduces a new feature to bind such device when the driver
is being loaded.

Signed-off-by: Wen Congyang <wency@...fujitsu.com>
---
 drivers/acpi/acpi_memhotplug.c |   37 ++++++++++++++++++++++++++++++++++++-
 1 files changed, 36 insertions(+), 1 deletions(-)

diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 3765375..0010720 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -52,6 +52,9 @@ MODULE_LICENSE("GPL");
 #define MEMORY_POWER_ON_STATE	1
 #define MEMORY_POWER_OFF_STATE	2
 
+static bool auto_probe;
+module_param(auto_probe, bool, S_IRUGO | S_IWUSR);
+
 static int acpi_memory_device_add(struct acpi_device *device);
 static int acpi_memory_device_remove(struct acpi_device *device, int type);
 
@@ -522,12 +525,44 @@ acpi_memory_register_notify_handler(acpi_handle handle,
 				    u32 level, void *ctxt, void **retv)
 {
 	acpi_status status;
-
+	struct acpi_memory_device *mem_device = NULL;
+	unsigned long long current_status;
 
 	status = is_memory_device(handle);
 	if (ACPI_FAILURE(status))
 		return AE_OK;	/* continue */
 
+	if (auto_probe) {
+		/* Get device present/absent information from the _STA */
+		status = acpi_evaluate_integer(handle, "_STA", NULL,
+					       &current_status);
+		if (ACPI_FAILURE(status))
+			goto install;
+
+		/*
+		 * Check for device status. Device should be
+		 * present/enabled/functioning.
+		 */
+		if (!(current_status &
+		      (ACPI_STA_DEVICE_PRESENT | ACPI_STA_DEVICE_ENABLED |
+		       ACPI_STA_DEVICE_FUNCTIONING)))
+			goto install;
+
+		if (acpi_memory_get_device(handle, &mem_device))
+			goto install;
+
+		/* We have bound this device while we register the driver */
+		if (mem_device->state == MEMORY_POWER_ON_STATE)
+			goto install;
+
+		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+				  "\nauto probe memory device\n"));
+
+		if (acpi_memory_enable_device(mem_device))
+			pr_err(PREFIX "Cannot enable memory device\n");
+	}
+
+install:
 	status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
 					     acpi_memory_device_notify, NULL);
 	/* continue */
-- 
1.7.1

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