linux-kernel - [PATCH 1/6] ACPI / PM: Change the way power transitions to D3cold are carried out

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 for Android: free password hash cracker in your pocket

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

Message-ID: <3421785.2lTFog1i8W@vostro.rjw.lan>
Date:	Fri, 04 Jan 2013 23:00:26 +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>,
	Lv Zheng <lv.zheng@...el.com>,
	Huang Ying <ying.huang@...el.com>
Subject: [PATCH 1/6] ACPI / PM: Change the way power transitions to D3cold are carried out

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

During power transitions into D3cold from any shallower power states
we are supposed to transition the device into D3hot and remove power
from it afterward, but the current code in acpi_device_set_power()
doesn't work this way.

At the same time, though, we need to be careful enough to preserve
backwards compatibility for systems that don't distinguish between
D3hot and D3cold (e.g. designed before ACPI 4).

Modify acpi_device_set_power() so that it works in accordance with
the expectations in both cases.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/acpi/bus.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

Index: linux/drivers/acpi/bus.c
===================================================================
--- linux.orig/drivers/acpi/bus.c
+++ linux/drivers/acpi/bus.c
@@ -270,6 +270,7 @@ int acpi_device_set_power(struct acpi_de
 	int result = 0;
 	acpi_status status = AE_OK;
 	char object_name[5] = { '_', 'P', 'S', '0' + state, '\0' };
+	bool cut_power = false;
 
 	if (!device || (state < ACPI_STATE_D0) || (state > ACPI_STATE_D3_COLD))
 		return -EINVAL;
@@ -294,9 +295,13 @@ int acpi_device_set_power(struct acpi_de
 		return -ENODEV;
 	}
 
-	/* For D3cold we should execute _PS3, not _PS4. */
-	if (state == ACPI_STATE_D3_COLD)
+	/* For D3cold we should first transition into D3hot. */
+	if (state == ACPI_STATE_D3_COLD
+	    && device->power.states[ACPI_STATE_D3_COLD].flags.os_accessible) {
+		state = ACPI_STATE_D3_HOT;
 		object_name[3] = '3';
+		cut_power = true;
+	}
 
 	/*
 	 * Transition Power
@@ -341,6 +346,9 @@ int acpi_device_set_power(struct acpi_de
 		}
 	}
 
+	if (cut_power)
+		result = acpi_power_transition(device, ACPI_STATE_D3_COLD);
+
       end:
 	if (result)
 		printk(KERN_WARNING PREFIX

--
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/