On Tuesday, October 30, 2012 04:53:28 PM Aaron Lu wrote:
> On 09/29/2012 05:55 AM, Rafael J. Wysocki wrote:
> > Define two device PM QoS flags, PM_QOS_FLAG_NO_POWER_OFF
> > and PM_QOS_FLAG_REMOTE_WAKEUP, and introduce routines
> > dev_pm_qos_expose_flags() and dev_pm_qos_hide_flags() allowing the
> > caller to expose those two flags to user space or to hide them
> > from it, respectively.
> >
> > After the flags have been exposed, user space will see two
> > additional sysfs attributes, pm_qos_no_power_off and
> > pm_qos_remote_wakeup, under the device's /sys/devices/.../power/
> > directory. Then, writing 1 to one of them will update the
> > PM QoS flags request owned by user space so that the corresponding
> > flag is requested to be set. In turn, writing 0 to one of them
> > will cause the corresponding flag in the user space's request to
> > be cleared (however, the owners of the other PM QoS flags requests
> > for the same device may still request the flag to be set and it
> > may be effectively set even if user space doesn't request that).
> >
> > Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
> > ---
> > Documentation/ABI/testing/sysfs-devices-power | 31 ++++
> > drivers/base/power/power.h | 6
> > drivers/base/power/qos.c | 169 ++++++++++++++++++++------
> > drivers/base/power/sysfs.c | 95 +++++++++++++-
> > include/linux/pm.h | 1
> > include/linux/pm_qos.h | 26 ++++
> > 6 files changed, 280 insertions(+), 48 deletions(-)
> >
> > Index: linux/drivers/base/power/qos.c
> > ===================================================================
> > --- linux.orig/drivers/base/power/qos.c
> > +++ linux/drivers/base/power/qos.c
> > @@ -40,6 +40,7 @@
> > #include <linux/device.h>
> > #include <linux/mutex.h>
> > #include <linux/export.h>
> > +#include <linux/pm_runtime.h>
> >
> > #include "power.h"
> >
> > @@ -322,6 +323,38 @@ int dev_pm_qos_add_request(struct device
> > EXPORT_SYMBOL_GPL(dev_pm_qos_add_request);
> >
> > /**
> > + * __dev_pm_qos_update_request - Modify an existing device PM QoS request.
> > + * @req : PM QoS request to modify.
> > + * @new_value: New value to request.
> > + */
> > +int __dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value)
> > +{
> > + s32 curr_value;
> > + int ret = 0;
> > +
> > + if (!req->dev->power.qos) {
> > + ret = -ENODEV;
> > + goto out;
> > + }
> > +
> > + switch(req->type) {
> > + case DEV_PM_QOS_LATENCY:
> > + curr_value = req->data.pnode.prio;
> > + break;
> > + case DEV_PM_QOS_FLAGS:
> > + curr_value = req->data.flr.flags;
> > + break;
> > + default:
> > + return -EINVAL;
> > + }
> > +
> > + if (curr_value != new_value)
> > + ret = apply_constraint(req, PM_QOS_UPDATE_REQ, new_value);
> > +
> > + return ret;
> > +}
> > +
> > +/**
> > * dev_pm_qos_update_request - modifies an existing qos request
> > * @req : handle to list element holding a dev_pm_qos request to use
> > * @new_value: defines the qos request
> > @@ -336,11 +369,9 @@ EXPORT_SYMBOL_GPL(dev_pm_qos_add_request
> > * -EINVAL in case of wrong parameters, -ENODEV if the device has been
> > * removed from the system
> > */
> > -int dev_pm_qos_update_request(struct dev_pm_qos_request *req,
> > - s32 new_value)
> > +int dev_pm_qos_update_request(struct dev_pm_qos_request *req, s32 new_value)
> > {
> > - s32 curr_value;
> > - int ret = 0;
> > + int ret;
> >
> > if (!req) /*guard against callers passing in null */
> > return -EINVAL;
> > @@ -350,29 +381,9 @@ int dev_pm_qos_update_request(struct dev
> > return -EINVAL;
> >
> > mutex_lock(&dev_pm_qos_mtx);
> > -
> > - if (!req->dev->power.qos) {
> > - ret = -ENODEV;
> > - goto out;
> > - }
> > -
> > - switch(req->type) {
> > - case DEV_PM_QOS_LATENCY:
> > - curr_value = req->data.pnode.prio;
> > - break;
> > - case DEV_PM_QOS_FLAGS:
> > - curr_value = req->data.flr.flags;
> > - break;
> > - default:
> > - ret = -EINVAL;
> > - goto out;
> > - }
> > -
> > - if (curr_value != new_value)
> > - ret = apply_constraint(req, PM_QOS_UPDATE_REQ, new_value);
> > -
> > - out:
> > + __dev_pm_qos_update_request(req, new_value);
>
> You forgot to assign the return value here.
Quite obviously. I'm going to apply the appended patch for that.
Thanks for spotting it!
Rafael
---
From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Subject: PM / QoS: Fix the return value of dev_pm_qos_update_request()
Commit e39473d (PM / QoS: Make it possible to expose PM QoS device)
flags to user space introduced __dev_pm_qos_update_request() to be
called internally by dev_pm_qos_update_request(), but forgot to make
the latter actually use the return value of the former. Fix this
mistake.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
---
drivers/base/power/qos.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: linux/drivers/base/power/qos.c
===================================================================
--- linux.orig/drivers/base/power/qos.c
+++ linux/drivers/base/power/qos.c
@@ -380,7 +380,7 @@ int dev_pm_qos_update_request(struct dev
return -EINVAL;
mutex_lock(&dev_pm_qos_mtx);
- __dev_pm_qos_update_request(req, new_value);
+ ret = __dev_pm_qos_update_request(req, new_value);
mutex_unlock(&dev_pm_qos_mtx);
return ret;
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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