Re: [PATCH 2/8] PM: suspend_block: Add driver to access suspend blockers from user-space

Arve Hjønnevåg
2010-04-29T23:41:57Z

2010/4/29 Rafael J. Wysocki <rjw@sisk.pl>:
> On Thursday 29 April 2010, Arve Hjønnevåg wrote:
>> 2010/4/28 Rafael J. Wysocki <rjw@sisk.pl>:
>> > On Thursday 29 April 2010, Arve Hjønnevåg wrote:
>> >> 2010/4/28 Rafael J. Wysocki <rjw@sisk.pl>:
>> >> > On Wednesday 28 April 2010, Arve Hjønnevåg wrote:
>> >> >> Add a misc device, "suspend_blocker", that allows user-space processes
>> >> >> to block auto suspend. The device has ioctls to create a suspend_blocker,
>> >> >> and to block and unblock suspend. To delete the suspend_blocker, close
>> >> >> the device.
>> >> >>
>> >> >> Signed-off-by: Arve Hjønnevåg <arve@android.com>
>> >> > ...
>> >> >> +
>> >> >> +#include <linux/fs.h>
>> >> >> +#include <linux/miscdevice.h>
>> >> >> +#include <linux/module.h>
>> >> >> +#include <linux/uaccess.h>
>> >> >> +#include <linux/slab.h>
>> >> >> +#include <linux/suspend_blocker.h>
>> >> >> +#include <linux/suspend_block_dev.h>
>> >> >> +
>> >> >> +enum {
>> >> >> +     DEBUG_FAILURE   = BIT(0),
>> >> >> +};
>> >> >> +static int debug_mask = DEBUG_FAILURE;
>> >> >
>> >> > What's the exact purpose of this?
>> >>
>> >> To show errors returned to user space. I can turn it off by default if you want.
>> >
>> > Not necessarily, but why is it a mask?  It looks like a 0/1 thing would be
>> > sufficient.
>>
>> I may want to add a bit to print all user-space block and unblock calls.
>
> Alternatively, you can add a new parameter for that, which I think I would prefer.
>

I use a bit-mask in the main suspend blocker code. This makes it easy
to turn on or off all the messages.

--
Arve Hjønnevåg