1. 17 10月, 2013 2 次提交
    • A
      ATA / ACPI: remove power dependent device handling · b08fc109
      Aaron Lu 提交于
      Previously, we wanted SCSI devices corrsponding to ATA devices to
      be runtime resumed when the power resource for those ATA device was
      turned on by some other device, so we added the SCSI device to the
      dependent device list of the ATA device's ACPI node.  However, this
      code has no effect after commit 41863fce (ACPI / power: Drop automaitc
      resume of power resource dependent devices) and the mechanism it was
      supposed to implement is regarded as a bad idea now, so drop it.
      
      [rjw: Changelog]
      Signed-off-by: NAaron Lu <aaron.lu@intel.com>
      Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      b08fc109
    • R
      ACPI / power: Drop automaitc resume of power resource dependent devices · 41863fce
      Rafael J. Wysocki 提交于
      The mechanism causing devices depending on a given power resource
      (that is, devices that can be in D0 only if that power resource is
      on) to be resumed automatically when the power resource is turned
      on (and their "inferred" power state becomes D0 as a result) is
      inherently racy and in fact unnecessary.
      
      It is racy, because if the power resource is turned on and then
      immediately off, the device resume triggered by the first transition
      to "on" may still happen, causing the power resource to be turned
      on again.  That again will trigger the "resume of dependent devices"
      mechanism, but if the devices in question are not in use, they will
      be suspended in the meantime causing the power resource to be turned
      off.  However, the "resume of dependent devices" will next resume
      them again and so on.  In some cases (USB port PM in particular) that
      leads to an endless busy loop of flipping the resource on and off
      continuously.
      
      It is needless, because whoever turns a power resource on will most
      likely turn it off at some point and the devices that go into "D0"
      as a result of turning it on will then go back into D3cold
      (generally, the state they were in before).
      
      Moreover, turning on all power resources a device needs to go into
      D0 is not sufficient for a full transition into D0 in general.
      Namely, _PS0 may need to be executed in addition to that in some
      cases.  This means that the whole rationale of the "resume of
      dependent devices" mechanism was incorrect to begin with and it's
      best to remove it entirely.
      Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      41863fce
  2. 16 10月, 2013 2 次提交
  3. 14 10月, 2013 3 次提交
  4. 12 10月, 2013 2 次提交
  5. 11 10月, 2013 9 次提交
  6. 10 10月, 2013 22 次提交