linux-kernel - [Update][PATCH] ACPI / PM: Export power states of ACPI devices via sysfs

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1982172.z1FZmGBJNL@vostro.rjw.lan>
Date:	Sat, 19 Jan 2013 21:53:32 +0100
From:	"Rafael J. Wysocki" <rjw@...k.pl>
To:	ACPI Devel Maling List <linux-acpi@...r.kernel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>, Len Brown <lenb@...nel.org>,
	"Kristen C. Accardi" <kristen.c.accardi@...el.com>
Subject: [Update][PATCH] ACPI / PM: Export power states of ACPI devices via sysfs

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
Subject: ACPI / PM: Export power states of ACPI devices via sysfs

Make it possible to retrieve the current power state of a device with
ACPI power management from user space via sysfs by adding a new
attribute power_state to the sysfs directory associated with the
struct acpi_device object representing the device's ACPI node.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---

I've changed my mind here.  It looks like it's more convenient to put the
power_state attribute directly into the ACPI device node's directory in sysfs
rather than into its power subdirectory.

Thanks,
Rafael

---
 Documentation/ABI/testing/sysfs-devices-power |   13 +++++++++++++
 drivers/acpi/scan.c                           |   25 ++++++++++++++++++++++++-
 2 files changed, 37 insertions(+), 1 deletion(-)

Index: linux-pm/drivers/acpi/scan.c
===================================================================
--- linux-pm.orig/drivers/acpi/scan.c
+++ linux-pm/drivers/acpi/scan.c
@@ -184,6 +184,19 @@ err_out:
 }
 EXPORT_SYMBOL(acpi_bus_hot_remove_device);
 
+static ssize_t power_state_show(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct acpi_device *adev = to_acpi_device(dev);
+	int state;
+	int ret;
+
+	ret = acpi_device_get_power(adev, &state);
+	return ret ? ret : sprintf(buf, "%s\n", acpi_power_state_string(state));
+}
+
+static DEVICE_ATTR(power_state, 0444, power_state_show, NULL);
+
 static ssize_t
 acpi_eject_store(struct device *d, struct device_attribute *attr,
 		const char *buf, size_t count)
@@ -375,8 +388,15 @@ static int acpi_device_setup_files(struc
          * hot-removal function from userland.
          */
 	status = acpi_get_handle(dev->handle, "_EJ0", &temp);
-	if (ACPI_SUCCESS(status))
+	if (ACPI_SUCCESS(status)) {
 		result = device_create_file(&dev->dev, &dev_attr_eject);
+		if (result)
+			goto end;
+	}
+
+	if (dev->flags.power_manageable)
+		result = device_create_file(&dev->dev, &dev_attr_power_state);
+
 end:
 	return result;
 }
@@ -386,6 +406,9 @@ static void acpi_device_remove_files(str
 	acpi_status status;
 	acpi_handle temp;
 
+	if (dev->flags.power_manageable)
+		device_remove_file(&dev->dev, &dev_attr_power_state);
+
 	/*
 	 * If device has _STR, remove 'description' file
 	 */

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/