Re: [PATCH] Driver Core fixes for 2.6.7-rc1

[Greg KH <greg@kroah.com>]

ChangeSet 1.1717.7.4, 2004/05/28 10:04:18-07:00, tpoynor@mvista.com

[PATCH] Device runtime suspend/resume fixes

(1) Set device power state at runtime resume (as is done for runtime
suspend) so that a later suspend does not think the device is still
suspended (refusing to suspend it again).

(2) Move devices from the active list to the off list only when
suspending all devices as part of a system suspend, not for runtime
suspend.  This matches the resume code, which only moves devices from
off to active during system resume, such that runtime resume currently
doesn't move the suspended device back to the active list.  (This also
avoids reordering the device list for runtime suspends; the list is in
order of registration and suspend/resume works best that way -- granted,
more sweeping improvements in how device dependencies are accounted for
in the suspend/resume order are also needed someday.)

Runtime device suspend/resume is in some cases used frequently on
battery-powered embedded devices, to save additional power and to handle
device power state interactions with overall system power state on
certain platforms.

Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>


 drivers/base/power/runtime.c |    5 ++++-
 drivers/base/power/suspend.c |   23 ++++++++++-------------
 2 files changed, 14 insertions(+), 14 deletions(-)


diff -Nru a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
--- a/drivers/base/power/runtime.c	Fri May 28 14:18:15 2004
+++ b/drivers/base/power/runtime.c	Fri May 28 14:18:15 2004
@@ -14,7 +14,10 @@
 {
 	if (!dev->power.power_state)
 		return;
-	resume_device(dev);
+	if (! resume_device(dev))
+		dev->power.power_state = 0;
+
+	return;
 }
 
 
diff -Nru a/drivers/base/power/suspend.c b/drivers/base/power/suspend.c
--- a/drivers/base/power/suspend.c	Fri May 28 14:18:15 2004
+++ b/drivers/base/power/suspend.c	Fri May 28 14:18:15 2004
@@ -42,13 +42,6 @@
 	if (dev->bus && dev->bus->suspend)
 		error = dev->bus->suspend(dev,state);
 
-	if (!error) {
-		list_del(&dev->power.entry);
-		list_add(&dev->power.entry,&dpm_off);
-	} else if (error == -EAGAIN) {
-		list_del(&dev->power.entry);
-		list_add(&dev->power.entry,&dpm_off_irq);
-	}
 	return error;
 }
 
@@ -81,12 +74,16 @@
 	while(!list_empty(&dpm_active)) {
 		struct list_head * entry = dpm_active.prev;
 		struct device * dev = to_device(entry);
-		if ((error = suspend_device(dev,state))) {
-			if (error != -EAGAIN)
-				goto Error;
-			else
-				error = 0;
-		}
+		error = suspend_device(dev,state);
+
+		if (!error) {
+			list_del(&dev->power.entry);
+			list_add(&dev->power.entry,&dpm_off);
+		} else if (error == -EAGAIN) {
+			list_del(&dev->power.entry);
+			list_add(&dev->power.entry,&dpm_off_irq);
+		} else
+			goto Error;
 	}
  Done:
 	up(&dpm_sem);