On 01/15/2017 06:49 AM, Rafael J. Wysocki wrote:
On Saturday, January 14, 2017 08:46:05 PM Guenter Roeck wrote:
Hi folks,
Hi,
while looking through driver initialization and removal functions, I noticed
that many drivers
call device_init_wakeup(dev, false) in the removal function. Given that the
driver is about
to be removed, that doesn't make much sense to me, especially since
device_wakeup_disable()
is called from device_pm_remove() anyway.
Is it safe to assume that all those calls can be removed, or is there a
possible reason for
keeping them around ?
Removing them automatically might break things, because device_init_wakeup(dev,
false)
also clears the power.can_wakeup flag and removes the "wakeup" attribute from
sysfs.
I had the same concern, but I concluded that the wakeup attribute should be
removed
automatically, since it is added with sysfs_merge_group(), and the matching
unmerge call
is also made in dpm_sysfs_remove(). power.can_wakeup is part of the device
structure,
which is in the process of being removed, so I am not sure I understand how
that can be
problematic.
I guess they could be removed safely in the majority of cases, though.
How would one decide if it is needed ? I see some drivers call it on remove,
but others
don't. I don't see a clear pattern; unless I am missing something, it seems to
be
more or less random.
Thanks,
Guenter
