On Wed, Jan 24, 2007 at 05:15:24PM -0800, Greg KH wrote:
> On Wed, Jan 24, 2007 at 11:51:17AM -0500, Alan Stern wrote:
> > On Tue, 23 Jan 2007, Greg KH wrote:
> >
> > > On Tue, Jan 23, 2007 at 04:22:43PM -0800, David Brownell wrote:
> > > > > > > static struct attribute *dev_attrs[] = {
> > > > > > > + /* power management attributes */
> > > > > > > + &dev_attr_autosuspend.attr,
> > > > > >
> > > > > > Belongs in /sys/devices/.../power/... then, right?
> > > > >
> > > > > No, I thought we want to drop that power/ directory.
> > > >
> > > > Dropping that directory hasn't AFAIK ever been discussed.
> > > > If it were to be dropped, where would the per-device wakeup
> > > > flags live?
> > >
> > > I don't know, it just really annoys me to see that power directory there
> > > with no use for it for a lot of devices :)
> >
> > 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?
thanks,
greg k-h
---
drivers/base/power/sysfs.c | 7 +++++--
drivers/pci/probe.c | 1 +
include/linux/device.h | 1 +
3 files changed, 7 insertions(+), 2 deletions(-)
--- gregkh-2.6.orig/drivers/base/power/sysfs.c
+++ gregkh-2.6/drivers/base/power/sysfs.c
@@ -156,10 +156,13 @@ 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_power)
+ 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_power)
+ sysfs_remove_group(&dev->kobj, &pm_attr_group);
}
--- gregkh-2.6.orig/drivers/pci/probe.c
+++ gregkh-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_power = 1;
dev->devfn = devfn;
dev->hdr_type = hdr_type & 0x7f;
dev->multifunction = !!(hdr_type & 0x80);
--- gregkh-2.6.orig/include/linux/device.h
+++ gregkh-2.6/include/linux/device.h
@@ -365,6 +365,7 @@ struct device {
char bus_id[BUS_ID_SIZE]; /* position on parent bus */
struct device_type *type;
unsigned is_registered:1;
+ unsigned supports_power:1;
struct device_attribute uevent_attr;
struct device_attribute *devt_attr;
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