From: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linux PM <linux-pm@vger.kernel.org>,
"open list:BLUETOOTH DRIVERS" <linux-bluetooth@vger.kernel.org>,
ChromeOS Bluetooth Upstreaming
<chromeos-bluetooth-upstreaming@chromium.org>,
Rafael Wysocki <rafael.j.wysocki@intel.com>,
Stephen Boyd <swboyd@chromium.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>
Subject: Re: [PATCH v4 1/1] power: Emit changed uevent on wakeup_sysfs_add/remove
Date: Tue, 7 Jul 2020 09:47:52 -0700 [thread overview]
Message-ID: <CANFp7mUas8Qnzqeivri25S7SWbKe6T+6riN419dR6xZXXOcaKA@mail.gmail.com> (raw)
In-Reply-To: <CAJZ5v0iyvge_Hqgm46_vfjh45YFdnsJ7ksvY7DqD6gx+f+1dvg@mail.gmail.com>
Hi Rafael,
(resent in plain text)
On Tue, Jul 7, 2020 at 9:28 AM Rafael J. Wysocki <rafael@kernel.org> wrote:
>
> On Tue, Jul 7, 2020 at 6:24 PM Abhishek Pandit-Subedi
> <abhishekpandit@chromium.org> wrote:
> >
> > Udev rules that depend on the power/wakeup attribute don't get triggered
> > correctly if device_set_wakeup_capable is called after the device is
> > created. This can happen for several reasons (driver sets wakeup after
> > device is created, wakeup is changed on parent device, etc) and it seems
> > reasonable to emit a changed event when adding or removing attributes on
> > the device.
> >
> > Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
> > ---
> >
> > Changes in v4:
> > - Fix warning where returning from void and tested on device
> >
> > Changes in v3:
> > - Simplified error handling
> >
> > Changes in v2:
> > - Add newline at end of bt_dev_err
> >
> > drivers/base/power/sysfs.c | 9 ++++++++-
> > 1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
> > index 24d25cf8ab1487..aeb58d40aac8de 100644
> > --- a/drivers/base/power/sysfs.c
> > +++ b/drivers/base/power/sysfs.c
> > @@ -1,6 +1,7 @@
> > // SPDX-License-Identifier: GPL-2.0
> > /* sysfs entries for device PM */
> > #include <linux/device.h>
> > +#include <linux/kobject.h>
> > #include <linux/string.h>
> > #include <linux/export.h>
> > #include <linux/pm_qos.h>
> > @@ -739,12 +740,18 @@ int dpm_sysfs_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid)
> >
> > int wakeup_sysfs_add(struct device *dev)
> > {
> > - return sysfs_merge_group(&dev->kobj, &pm_wakeup_attr_group);
> > + int ret = sysfs_merge_group(&dev->kobj, &pm_wakeup_attr_group);
> > +
> > + if (ret)
> > + return ret;
> > +
> > + return kobject_uevent(&dev->kobj, KOBJ_CHANGE);
>
> So let me repeat the previous comment:
>
> If you return an error here, it may confuse the caller to think that
> the operation has failed completely, whereas the merging of the
> attribute group has been successful already.
>
> I don't think that an error can be returned at this point.
>
The caller looks at the return code and just logs that an error
occurred (no other action). It's also unlikely for kobject_uevent to
fail (I saw mostly -ENOMEM and an -ENOENT when the kobj wasn't in the
correct set).
Call site:
int ret = wakeup_sysfs_add(dev);
if (ret)
dev_info(dev, "Wakeup sysfs attributes not added\n");
So I'm ok with either keeping this as-is (caller isn't getting
confused, just logging) or swallowing the return of kobject_uevent.
> > }
> >
> > void wakeup_sysfs_remove(struct device *dev)
> > {
> > sysfs_unmerge_group(&dev->kobj, &pm_wakeup_attr_group);
> > + kobject_uevent(&dev->kobj, KOBJ_CHANGE);
> > }
> >
> > int pm_qos_sysfs_add_resume_latency(struct device *dev)
> > --
> > 2.27.0.212.ge8ba1cc988-goog
> >
next prev parent reply other threads:[~2020-07-07 16:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 16:24 [PATCH v4 0/1] power: Emit change uevent when updating sysfs Abhishek Pandit-Subedi
2020-07-07 16:24 ` [PATCH v4 1/1] power: Emit changed uevent on wakeup_sysfs_add/remove Abhishek Pandit-Subedi
2020-07-07 16:26 ` Abhishek Pandit-Subedi
2020-07-07 16:28 ` Rafael J. Wysocki
2020-07-07 16:47 ` Abhishek Pandit-Subedi [this message]
2020-07-07 17:16 ` Rafael J. Wysocki
2020-07-07 17:18 ` Abhishek Pandit-Subedi
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