Currently acpi_run_osc() checks all the bits in _OSC result code (the
first DWORD in the capabilities buffer) to see error condition. But the
bit 0, which doesn't indicate any error, must be ignored.
The bit 0 is used as the query flag at _OSC invocation time. Some
platforms clear it during _OSC evaluation, but the others don't. On
latter platforms, current acpi_run_osc() mis-detects error when _OSC is
evaluated with query flag set because it doesn't ignore the bit 0.
Because of this, the __acpi_query_osc() always fails on such platforms.
And this is the cause of the problem that pci_osc_control_set() doesn't
work since the commit 4e39432f4d which
changed pci_osc_control_set() to use __acpi_query_osc().
Tested-by:"Tomasz Czernecki <czernecki@gmail.com>
Signed-off-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2485b8674b