On Tuesday 07 April 2009, Michael Trimarchi wrote:
> Hi,
>
> Rafael J. Wysocki wrote:
> > On Tuesday 07 April 2009, Michael Trimarchi wrote:
> >
> >> This is a little rework of linux power scheme. TODO:
> >> - remove recursive call
> >> - clean-up code
> >>
> >> Avoid suspend of a device that is connected with other coprocessor
> >> like GSM chip.
> >>
> >
> > Well, can you please tell us a bit about the motivation for this work?
> >
> > I don't like the approach, but I'd like to know what you're trying to achieve.
> >
> I works on an hardware that have the gsm connect to wm8753 and the
> bluetooth subsystem
> too direct connected. So I would like that a phone call for example
> remains on during
> system suspend. With this approch I can disable suspend of an entire
> subtree of device,
> that can be used by other hardware component. This change avoid any
> specific change to the
> driver.
Why do you want to avoid changing the driver, actually?
Rafael
> >> Signed-off-by: Michael Trimarchi <trimarchi@xxxxxxxxxxxxxxxx>
> >>
> >> ---
> >> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> >> index 3098c46..2a6ddb3 100644
> >> --- a/drivers/base/power/main.c
> >> +++ b/drivers/base/power/main.c
> >> @@ -63,6 +63,40 @@ void device_pm_unlock(void)
> >> mutex_unlock(&dpm_list_mtx);
> >> }
> >>
> >> +int device_set_may_suspend_enable(struct device *dev, void *data)
> >> +{
> >> + /* if the device is suspend the subtree is in may_suspend status */
> >> + if (!dev->power.can_suspend)
> >> + goto out;
> >> +
> >> + dev->power.may_suspend = (unsigned int)data;
> >> + device_for_each_child(dev, data,
> >> + device_set_may_suspend_enable);
> >> +out:
> >> + return 0;
> >> +}
> >> +
> >> +/**
> >> + * device_set_suspend_enable - enable/disable device to suspend
> >> + */
> >> +int device_set_suspend_enable(struct device *dev, int enable)
> >> +{
> >> + mutex_lock(&dpm_list_mtx);
> >> +
> >> + if (dev->power.can_suspend == !!enable)
> >> + goto out;
> >> +
> >> + /* Update device children to avoid suspend */
> >> + device_for_each_child(dev, (void *)!!enable,
> >> + device_set_may_suspend_enable);
> >> +
> >> + dev->power.can_suspend = !!enable;
> >> +out:
> >> + mutex_unlock(&dpm_list_mtx);
> >> + return 0;
> >> +}
> >> +EXPORT_SYMBOL_GPL(device_set_suspend_enable);
> >> +
> >> /**
> >> * device_pm_add - add a device to the list of active devices
> >> * @dev: Device to be added to the list
> >> @@ -77,6 +111,13 @@ void device_pm_add(struct device *dev)
> >> if (dev->parent->power.status >= DPM_SUSPENDING)
> >> dev_warn(dev, "parent %s should not be sleeping\n",
> >> dev_name(dev->parent));
> >> + if (!device_can_suspend(dev->parent)) {
> >> + mutex_unlock(&dpm_list_mtx);
> >> + /* if the parent has suspend disable, propagate it
> >> + * to the new child */
> >> + device_set_may_suspend_enable(dev, 0);
> >> + mutex_lock(&dpm_list_mtx);
> >> + }
> >> } else if (transition_started) {
> >> /*
> >> * We refuse to register parentless devices while a PM
> >> @@ -120,13 +161,13 @@ static int pm_op(struct device *dev, struct dev_pm_ops *ops,
> >> switch (state.event) {
> >> #ifdef CONFIG_SUSPEND
> >> case PM_EVENT_SUSPEND:
> >> - if (ops->suspend) {
> >> + if (device_can_suspend(dev) && ops->suspend) {
> >> error = ops->suspend(dev);
> >> suspend_report_result(ops->suspend, error);
> >> }
> >> break;
> >> case PM_EVENT_RESUME:
> >> - if (ops->resume) {
> >> + if (device_can_suspend(dev) && ops->resume) {
> >> error = ops->resume(dev);
> >> suspend_report_result(ops->resume, error);
> >> }
> >> diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h
> >> index 41f51fa..1197b13 100644
> >> --- a/drivers/base/power/power.h
> >> +++ b/drivers/base/power/power.h
> >> @@ -1,6 +1,13 @@
> >> static inline void device_pm_init(struct device *dev)
> >> {
> >> dev->power.status = DPM_ON;
> >> + dev->power.can_suspend = 1;
> >> + dev->power.may_suspend = 1;
> >> +}
> >> +
> >> +static inline int device_can_suspend(struct device *dev)
> >> +{
> >> + return (dev->power.can_suspend && dev->power.may_suspend);
> >> }
> >>
> >> #ifdef CONFIG_PM_SLEEP
> >> diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
> >> index 596aeec..25236aa 100644
> >> --- a/drivers/base/power/sysfs.c
> >> +++ b/drivers/base/power/sysfs.c
> >> @@ -43,6 +43,34 @@
> >> static const char enabled[] = "enabled";
> >> static const char disabled[] = "disabled";
> >>
> >> +static ssize_t suspend_show(struct device *dev, struct device_attribute *attr,
> >> + char *buf)
> >> +{
> >> + return sprintf(buf, "%s\n", device_can_suspend(dev)
> >> + ? enabled : disabled);
> >> +}
> >> +
> >> +static ssize_t
> >> +suspend_store(struct device *dev, struct device_attribute *attr,
> >> + const char *buf, size_t n)
> >> +{
> >> + char *cp;
> >> + int len = n;
> >> +
> >> + cp = memchr(buf, '\n', n);
> >> + if (cp)
> >> + len = cp - buf;
> >> + if (len == sizeof enabled - 1
> >> + && strncmp(buf, enabled, sizeof enabled - 1) == 0)
> >> + device_set_suspend_enable(dev, 1);
> >> + else if (len == sizeof disabled - 1
> >> + && strncmp(buf, disabled, sizeof disabled - 1) == 0)
> >> + device_set_suspend_enable(dev, 0);
> >> + else
> >> + return -EINVAL;
> >> + return n;
> >> +}
> >> +
> >> static ssize_t
> >> wake_show(struct device * dev, struct device_attribute *attr, char * buf)
> >> {
> >> @@ -76,10 +104,11 @@ wake_store(struct device * dev, struct device_attribute *attr,
> >> }
> >>
> >> static DEVICE_ATTR(wakeup, 0644, wake_show, wake_store);
> >> -
> >> +static DEVICE_ATTR(suspend, 0644, suspend_show, suspend_store);
> >>
> >> static struct attribute * power_attrs[] = {
> >> &dev_attr_wakeup.attr,
> >> + &dev_attr_suspend.attr,
> >> NULL,
> >> };
> >> static struct attribute_group pm_attr_group = {
> >> diff --git a/include/linux/device.h b/include/linux/device.h
> >> index fdb073b..dc9f242 100644
> >> --- a/include/linux/device.h
> >> +++ b/include/linux/device.h
> >> @@ -487,6 +487,7 @@ extern struct device *device_find_child(struct device *dev, void *data,
> >> int (*match)(struct device *dev, void *data));
> >> extern int device_rename(struct device *dev, char *new_name);
> >> extern int device_move(struct device *dev, struct device *new_parent);
> >> +extern int device_set_suspend_enable(struct device *dev, int enable);
> >>
> >> /*
> >> * Root device objects for grouping under /sys/devices
> >> diff --git a/include/linux/pm.h b/include/linux/pm.h
> >> index de2e0a8..7586a90 100644
> >> --- a/include/linux/pm.h
> >> +++ b/include/linux/pm.h
> >> @@ -319,6 +319,9 @@ struct dev_pm_info {
> >> pm_message_t power_state;
> >> unsigned can_wakeup:1;
> >> unsigned should_wakeup:1;
> >> + unsigned can_suspend:1;
> >> + unsigned may_suspend:1;
> >> +
> >> enum dpm_state status; /* Owned by the PM core */
> >> #ifdef CONFIG_PM_SLEEP
> >> struct list_head entry;
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