linux-kernel - [RFC][PATCH v3 3/3] input: i8042: Avoid resetting controller on system suspend/resume

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]

Date:	Wed, 07 Oct 2015 00:53:49 +0200
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	Linux PM list <linux-pm@...r.kernel.org>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
	Alan Stern <stern@...land.harvard.edu>,
	Daniel Vetter <daniel.vetter@...el.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Linux PCI <linux-pci@...r.kernel.org>
Subject: [RFC][PATCH v3 3/3] input: i8042: Avoid resetting controller on system suspend/resume

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

If the upcoming system suspend is not going to be handled by the
platform firmware, like in the suspend-to-idle case, it is not
necessary to reset the controller in i8042_pm_suspend(), so avoid
doing that.

Moreover, if the system resume currently in progress has not been
started by the platform firmware, like in the suspend-to-idle case,
i8042_controller_resume() need not be called by i8042_pm_resume(),
so avoid doing that too in that case.

Additionally, try to catch the event that woke up the system by
calling the interrupt handler early during system resume if it has
not been started by the platform firmware.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/input/serio/i8042.c |   15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

Index: linux-pm/drivers/input/serio/i8042.c
===================================================================
--- linux-pm.orig/drivers/input/serio/i8042.c
+++ linux-pm/drivers/input/serio/i8042.c
@@ -24,6 +24,7 @@
 #include <linux/platform_device.h>
 #include <linux/i8042.h>
 #include <linux/slab.h>
+#include <linux/suspend.h>
 
 #include <asm/io.h>
 
@@ -1170,7 +1171,8 @@ static int i8042_pm_suspend(struct devic
 {
 	int i;
 
-	i8042_controller_reset(true);
+	if (pm_suspend_via_firmware())
+		i8042_controller_reset(true);
 
 	/* Set up serio interrupts for system wakeup. */
 	for (i = 0; i < I8042_NUM_PORTS; i++) {
@@ -1183,6 +1185,14 @@ static int i8042_pm_suspend(struct devic
 	return 0;
 }
 
+static int i8042_pm_resume_noirq(struct device *dev)
+{
+	if (!pm_resume_via_firmware())
+		i8042_interrupt(0, NULL);
+
+	return 0;
+}
+
 static int i8042_pm_resume(struct device *dev)
 {
 	int i;
@@ -1199,7 +1209,7 @@ static int i8042_pm_resume(struct device
 	 * to bring it in a sane state. (In case of S2D we expect
 	 * BIOS to reset the controller for us.)
 	 */
-	return i8042_controller_resume(true);
+	return pm_resume_via_firmware() ? i8042_controller_resume(true) : 0;
 }
 
 static int i8042_pm_thaw(struct device *dev)
@@ -1223,6 +1233,7 @@ static int i8042_pm_restore(struct devic
 
 static const struct dev_pm_ops i8042_pm_ops = {
 	.suspend	= i8042_pm_suspend,
+	.resume_noirq	= i8042_pm_resume_noirq,
 	.resume		= i8042_pm_resume,
 	.thaw		= i8042_pm_thaw,
 	.poweroff	= i8042_pm_reset,

--
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/