path: root/include/acpi
diff options
authorRafael J. Wysocki <rjw@sisk.pl>2010-08-23 23:55:59 +0200
committerJesse Barnes <jbarnes@virtuousgeek.org>2010-08-24 13:44:17 -0700
commit2b8fd9186d9275b07aef43e5bb4e98cd571f9a7d (patch)
tree8ddae8c12e8dabfffb3eed75aff0f3121b955e9c /include/acpi
parentab8e8957a2ae21c0f036476c6db13e949be730ac (diff)
ACPI/PCI: Do not preserve _OSC control bits returned by a query
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: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'include/acpi')
1 files changed, 0 insertions, 3 deletions
diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index baacd98e7cc..4de84ce3a92 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -377,9 +377,6 @@ struct acpi_pci_root {
u32 osc_support_set; /* _OSC state of support bits */
u32 osc_control_set; /* _OSC state of control bits */
- u32 osc_control_qry; /* the latest _OSC query result */
- u32 osc_queried:1; /* has _OSC control been queried? */
/* helper */