[lkml]   [2010]   [May]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [linux-pm] [PATCH 1/8] PM: Add suspend block api.
    On Mon, 3 May 2010, mark gross wrote:

    > You know things would be so much easier if the policy was a one-shot
    > styled thing. i.e. when enabled it does what it does, but upon resume
    > the policy must be re-enabled by user mode to get the opportunistic
    > behavior. That way we don't need to grab the suspend blocker from the
    > wake up irq handler all the way up to user mode as the example below
    > calls out. I suppose doing this would put a burden on the user mode code
    > to keep track of if it has no pending blockers registered after a wake
    > up from the suspend. but that seems nicer to me than sprinkling
    > overlapping blocker critical sections from the mettle up to user mode.
    > Please consider making the policy a one shot API that needs to be
    > re-enabled after resume by user mode. That would remove my issue with
    > the design.

    This won't work right if a second IRQ arrives while the first is being
    processed. Suppose the kernel driver for the second IRQ doesn't
    activate a suspend blocker, and suppose all the userspace handlers for
    the first IRQ end (and the opportunistic policy is re-enabled) before
    the userspace handler for the second IRQ can start. Then the system
    will go back to sleep before userspace can handle the second IRQ.

    Alan Stern

     \ /
      Last update: 2010-05-04 16:03    [W:0.025 / U:6.856 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site