On Wed, 24 Jan 2007, Greg KH wrote:
> > > Would it help to add a flag somewhere in struct device (or struct
> > > dev_pm_info) for indicating that the device is not cognizant of PM? For
> > > instance, all those USB endpoint pseudo-devices we create -- it's a waste
> > > of time to try doing power management on them and it generates a bunch of
> > > useless and distracting warning messages in the system log.
> >
> > Yes. In fact we should just make it a "has pm" type flag, as the
> > majority of devices do not.
> >
> > So, what kind of devices do support these files? I can think of:
> > PCI
> > USB
> > and that's it right now. Do platform devices really use those files?
>
> Something as simple as this patch perhaps?
I had something bigger in mind. More like the patch below (completely
untested). Plus of course code to turn off the new flag for the
appropriate devices.
Alan Stern
Index: usb-2.6/drivers/base/power/sysfs.c
===================================================================
--- usb-2.6.orig/drivers/base/power/sysfs.c
+++ usb-2.6/drivers/base/power/sysfs.c
@@ -152,10 +152,13 @@ static struct attribute_group pm_attr_gr
int dpm_sysfs_add(struct device * dev)
{
- return sysfs_create_group(&dev->kobj, &pm_attr_group);
+ if (dev->supports_pm)
+ return sysfs_create_group(&dev->kobj, &pm_attr_group);
+ return 0;
}
void dpm_sysfs_remove(struct device * dev)
{
- sysfs_remove_group(&dev->kobj, &pm_attr_group);
+ if (dev->supports_pm)
+ sysfs_remove_group(&dev->kobj, &pm_attr_group);
}
Index: usb-2.6/drivers/pci/probe.c
===================================================================
--- usb-2.6.orig/drivers/pci/probe.c
+++ usb-2.6/drivers/pci/probe.c
@@ -893,6 +893,7 @@ pci_scan_device(struct pci_bus *bus, int
dev->sysdata = bus->sysdata;
dev->dev.parent = bus->bridge;
dev->dev.bus = &pci_bus_type;
+ dev->dev.supports_pm = 1;
dev->devfn = devfn;
dev->hdr_type = hdr_type & 0x7f;
dev->multifunction = !!(hdr_type & 0x80);
Index: usb-2.6/include/linux/device.h
===================================================================
--- usb-2.6.orig/include/linux/device.h
+++ usb-2.6/include/linux/device.h
@@ -367,6 +367,7 @@ struct device {
char bus_id[BUS_ID_SIZE]; /* position on parent bus */
struct device_type *type;
unsigned is_registered:1;
+ unsigned supports_pm:1;
struct device_attribute uevent_attr;
struct device_attribute *devt_attr;
Index: usb-2.6/drivers/base/power/resume.c
===================================================================
--- usb-2.6.orig/drivers/base/power/resume.c
+++ usb-2.6/drivers/base/power/resume.c
@@ -24,6 +24,9 @@ int resume_device(struct device * dev)
{
int error = 0;
+ if (!dev->supports_pm)
+ return error;
+
TRACE_DEVICE(dev);
TRACE_RESUME(0);
down(&dev->sem);
@@ -52,6 +55,9 @@ static int resume_device_early(struct de
{
int error = 0;
+ if (!dev->supports_pm)
+ return error;
+
TRACE_DEVICE(dev);
TRACE_RESUME(0);
if (dev->bus && dev->bus->resume_early) {
Index: usb-2.6/drivers/base/power/suspend.c
===================================================================
--- usb-2.6.orig/drivers/base/power/suspend.c
+++ usb-2.6/drivers/base/power/suspend.c
@@ -50,6 +50,9 @@ int suspend_device(struct device * dev,
{
int error = 0;
+ if (!dev->supports_pm)
+ return error;
+
down(&dev->sem);
if (dev->power.power_state.event) {
dev_dbg(dev, "PM: suspend %d-->%d\n",
@@ -103,7 +106,8 @@ static int suspend_device_late(struct de
{
int error = 0;
- if (dev->bus && dev->bus->suspend_late &&
!dev->power.power_state.event) {
+ if (dev->supports_pm && dev->bus && dev->bus->suspend_late &&
+ !dev->power.power_state.event) {
dev_dbg(dev, "LATE %s%s\n",
suspend_verb(state.event),
((state.event == PM_EVENT_SUSPEND)
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