On Friday, July 30, 2010, Kenji Kaneshige wrote:
> Currently, all the _OSC controls are queried at the same time in
> acpi_pci_osc_support() and the result is preserved for later
> acpi_pci_osc_control_set() call. But query result can vary depending
> on the combination of requested controls. Therefore, query result must
> not be preserved.
>
> Signed-off-by: Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx>
IMHO it would be _much_ simpler to change the definition of
acpi_pci_osc_control_get() in my original patch so that it executes
acp_pci_query_osc() unconditionally.
Rafael
> ---
> drivers/acpi/pci_root.c | 49 ++++++++++++++++++++++++++----------------------
> include/acpi/acpi_bus.h | 3 --
> 2 files changed, 27 insertions(+), 25 deletions(-)
>
> Index: linux-2.6.35-rc6/drivers/acpi/pci_root.c
> ===================================================================
> --- linux-2.6.35-rc6.orig/drivers/acpi/pci_root.c
> +++ linux-2.6.35-rc6/drivers/acpi/pci_root.c
> @@ -230,35 +230,42 @@ static acpi_status acpi_pci_run_osc(acpi
> return status;
> }
>
> -static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root, u32 flags)
> +static acpi_status acpi_pci_osc_control_query(struct acpi_pci_root *root,
> + u32 flags, u32 *result)
> {
> - acpi_status status;
> - u32 result;
> -
> - /* do _OSC query for all possible controls */
> - flags &= OSC_PCI_SUPPORT_MASKS;
> - status = acpi_pci_run_osc(root->device->handle,
> - root->osc_support_set | flags,
> - OSC_PCI_CONTROL_MASKS,
> - true, &result);
> - if (ACPI_SUCCESS(status)) {
> - root->osc_support_set |= flags;
> - root->osc_control_qry = result;
> - root->osc_queried = 1;
> + /* No need to run _OSC if requested control bits are already granted */
> + flags &= OSC_PCI_CONTROL_MASKS;
> + if ((root->osc_control_set & flags) == flags) {
> + *result = root->osc_control_set;
> + return AE_OK;
> }
> - return status;
> + return acpi_pci_run_osc(root->device->handle,
> + root->osc_support_set,
> + root->osc_control_set | flags,
> + true, result);
> }
>
> static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)
> {
> acpi_status status;
> acpi_handle tmp;
> + u32 result;
>
> status = acpi_get_handle(root->device->handle, "_OSC", &tmp);
> if (ACPI_FAILURE(status))
> return status;
> mutex_lock(&osc_lock);
> - status = acpi_pci_query_osc(root, flags);
> + /* No need to run _OSC if requested support bits are already set */
> + flags &= OSC_PCI_SUPPORT_MASKS;
> + if ((root->osc_support_set & flags) == flags)
> + goto out;
> + status = acpi_pci_run_osc(root->device->handle,
> + root->osc_support_set | flags,
> + root->osc_control_set,
> + true, &result);
> + if (ACPI_SUCCESS(status))
> + root->osc_support_set |= flags;
> +out:
> mutex_unlock(&osc_lock);
> return status;
> }
> @@ -399,12 +406,10 @@ acpi_status acpi_pci_osc_control_set(acp
> goto out;
>
> /* Need to query controls first before requesting them */
> - if (!root->osc_queried) {
> - status = acpi_pci_query_osc(root, root->osc_support_set);
> - if (ACPI_FAILURE(status))
> - goto out;
> - }
> - if ((root->osc_control_qry & control_req) != control_req) {
> + status = acpi_pci_osc_control_query(root, control_req, &result);
> + if (ACPI_FAILURE(status))
> + goto out;
> + if ((result & control_req) != control_req) {
> printk(KERN_DEBUG
> "Firmware did not grant requested _OSC control\n");
> status = AE_SUPPORT;
> Index: linux-2.6.35-rc6/include/acpi/acpi_bus.h
> ===================================================================
> --- linux-2.6.35-rc6.orig/include/acpi/acpi_bus.h
> +++ linux-2.6.35-rc6/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 */
>
>
>
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