Re: Attempted summary of suspend-blockers LKML thread

Brian Swetland
2010-08-05T14:23:04Z

On Thu, Aug 5, 2010 at 7:16 AM, Matthew Garrett <mjg59@srcf.ucam.org> wrote:
> On Thu, Aug 05, 2010 at 07:07:06AM -0700, david@lang.hm wrote:
>> On Thu, 5 Aug 2010, Matthew Garrett wrote:
>>> The decision on whether or not to go to sleep isn't the difficult bit of
>>> this problem space.
>>
>> but isn't that all that wakelocks do? affect the decision on whether or
>> not to go to sleep.
>
> You could think of them that way, but it's not the useful aspect of them
> - that much could be implemented entirely in userspace. Wakelocks
> provide a mechanism for userspace to ensure that it's handled all
> received events before a system suspend takes place.

For userspace or the kernel -- some events may not require userspace
intervention, but do require the kernel to stay awake long enough to
finish chewing on them. Say perhaps a wifi irq comes in, the wifi
driver/stack needs to process some beacon packets or whatnot.

Brian