1. 25 8月, 2010 1 次提交
    • R
      ACPI/PCI: Do not preserve _OSC control bits returned by a query · 2b8fd918
      Rafael J. Wysocki 提交于
      There is the assumption in acpi_pci_osc_control_set() that it is
      always sufficient to compare the mask of _OSC control bits to be
      requested with the result of an _OSC query where all of the known
      control bits have been checked.  However, in general, that need not
      be the case.  For example, if an _OSC feature A depends on an _OSC
      feature B and control of A, B plus another _OSC feature C is
      requested simultaneously, the BIOS may return A, B, C, while it would
      only return C if A and C were requested without B.
      
      That may result in passing a wrong mask of _OSC control bits to an
      _OSC control request, in which case the BIOS may only grant control
      of a subset of the requested features.  Moreover, acpi_pci_run_osc()
      will return error code if that happens and the caller of
      acpi_pci_osc_control_set() will not know that it's been granted
      control of some _OSC features.  Consequently, the system will
      generally not work as expected.
      
      Apart from this acpi_pci_osc_control_set() always uses the mask
      of _OSC control bits returned by the very first invocation of
      acpi_pci_query_osc(), but that is done with the second argument
      equal to OSC_PCI_SEGMENT_GROUPS_SUPPORT which generally happens
      to affect the returned _OSC control bits.
      
      For these reasons, make acpi_pci_osc_control_set() always check if
      control of the requested _OSC features will be granted before making
      the final control request.  As a result, the osc_control_qry and
      osc_queried members of struct acpi_pci_root are not necessary any
      more, so drop them and remove the remaining code referring to them.
      Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
      Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
      2b8fd918
  2. 14 8月, 2010 1 次提交
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  5. 11 8月, 2010 9 次提交