On Thursday, August 05, 2010, Rafael J. Wysocki wrote:
> On Wednesday, August 04, 2010, Kenji Kaneshige wrote:
> > (2010/08/04 5:58), Rafael J. Wysocki wrote:
> > > On Tuesday, August 03, 2010, Rafael J. Wysocki wrote:
> > >> On Tuesday, August 03, 2010, Kenji Kaneshige wrote:
> > >>> (2010/08/03 6:53), Rafael J. Wysocki wrote:
> > >>>> From: Rafael J. Wysocki<rjw@xxxxxxx>
> > >>>
> > >>> <snip.>
> > >>>
> > >>>> + mutex_lock(&osc_lock);
> > >>>> + status = acpi_pci_query_osc(root, root->osc_support_set, ctrl_mask);
> > >>>> + mutex_unlock(&osc_lock);
> > >>>> +
> > >>>
> > >>> One more comment here.
> > >>>
> > >>> I think we can skip acpi_pci_query_osc() if all of queried controls are
> > >>> already granted to OS. Please see below
> > >>>
> > >>> mutex_lock(&osc_lock);
> > >>> if ((root->osc_control_set& *ctrl_mask) == *ctrl_mask) {
> > >>> *ctrl_mask = root->osc_control_set;
> > >>> goto out;
> > >>> }
> > >>> status = acpi_pci_query_osc(root, root->osc_support_set, ctrl_mask);
> > >>> mutex_unlock(&osc_lock);
> > >>> out:
> > >>
> > >> Well I guess you mean:
> > >>
> > >> mutex_lock(&osc_lock);
> > >> if ((root->osc_control_set& *ctrl_mask) != *ctrl_mask)
> > >> status = acpi_pci_query_osc(root, root->osc_support_set, ctrl_mask);
> > >> mutex_unlock(&osc_lock);
> > >>
> > >> Otherwise we would return with the mutex held. :-)
> > >
> >
> > Oops... sorry...
> >
> > > Updated patch is appended, please tell me what you think.
> >
> > Looks good to me. The below (in your updated patch) was what I wanted to mean
> >
> > > + mutex_lock(&osc_lock);
> > > + if ((*mask & root->osc_control_set) == *mask)
> > > + *mask = root->osc_control_set;
> > > + else
> > > + status = acpi_pci_query_osc(root, root->osc_support_set, mask);
> > > + mutex_unlock(&osc_lock);
>
> OK
>
> However, I think we can put the looping into that function so that the caller
> doesn't have to loop.
>
> The patch below implements that.
The patch below is incorrect, sorry. Please disregard it.
Thanks,
Rafael
> ---
> From: Rafael J. Wysocki <rjw@xxxxxxx>
> Subject: ACPI / PCI: Introduce acpi_pci_osc_control_query() (v3)
>
> Introduce a function allowing the caller to obtain a mask of _OSC
> control bits the BIOS will allow the kernel to control for a given
> PCI root bridge.
>
> Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
> ---
> drivers/acpi/pci_root.c | 71 +++++++++++++++++++++++++++++++++++++++++-------
> include/linux/acpi.h | 1
> 2 files changed, 63 insertions(+), 9 deletions(-)
>
> Index: linux-2.6/drivers/acpi/pci_root.c
> ===================================================================
> --- linux-2.6.orig/drivers/acpi/pci_root.c
> +++ linux-2.6/drivers/acpi/pci_root.c
> @@ -225,21 +225,32 @@ 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_query_osc(struct acpi_pci_root *root,
> + u32 support,
> + u32 *control)
> {
> acpi_status status;
> - u32 support_set, result, capbuf[3];
> + u32 result, capbuf[3];
> +
> + support &= OSC_PCI_SUPPORT_MASKS;
> + support |= root->osc_support_set;
>
> - /* do _OSC query for all possible controls */
> - support_set = root->osc_support_set | (flags & OSC_PCI_SUPPORT_MASKS);
> capbuf[OSC_QUERY_TYPE] = OSC_QUERY_ENABLE;
> - capbuf[OSC_SUPPORT_TYPE] = support_set;
> - capbuf[OSC_CONTROL_TYPE] = OSC_PCI_CONTROL_MASKS;
> + capbuf[OSC_SUPPORT_TYPE] = support;
> + if (control) {
> + *control &= OSC_PCI_CONTROL_MASKS;
> + capbuf[OSC_CONTROL_TYPE] = *control | root->osc_control_set;
> + } else {
> + /* Run _OSC query for all possible controls. */
> + capbuf[OSC_CONTROL_TYPE] = OSC_PCI_CONTROL_MASKS;
> + }
>
> status = acpi_pci_run_osc(root->device->handle, capbuf, &result);
> if (ACPI_SUCCESS(status)) {
> - root->osc_support_set = support_set;
> + root->osc_support_set = support;
> root->osc_control_qry = result;
> + if (control)
> + *control = result;
> root->osc_queried = 1;
> }
> return status;
> @@ -254,7 +265,7 @@ static acpi_status acpi_pci_osc_support(
> if (ACPI_FAILURE(status))
> return status;
> mutex_lock(&osc_lock);
> - status = acpi_pci_query_osc(root, flags);
> + status = acpi_pci_query_osc(root, flags, NULL);
> mutex_unlock(&osc_lock);
> return status;
> }
> @@ -363,6 +374,48 @@ out:
> }
> EXPORT_SYMBOL_GPL(acpi_get_pci_dev);
>
> + /**
> + * acpi_pci_osc_control_query - Get the _OSC bits the kernel can control.
> + * @handle: ACPI handle of a PCI root bridge (or PCIe Root Complex).
> + * @mask: Mask of _OSC bits to query and the place to put the result into.
> + **/
> +acpi_status acpi_pci_osc_control_query(acpi_handle handle, u32 *mask)
> +{
> + struct acpi_pci_root *root;
> + acpi_handle tmp;
> + acpi_status status = AE_OK;
> + u32 ctrl = *mask;
> +
> + if (!ctrl || !(ctrl & OSC_PCI_CONTROL_MASKS))
> + return AE_BAD_PARAMETER;
> +
> + root = acpi_pci_find_root(handle);
> + if (!root)
> + return AE_NOT_EXIST;
> +
> + status = acpi_get_handle(handle, "_OSC", &tmp);
> + if (ACPI_FAILURE(status))
> + return status;
> +
> + mutex_lock(&osc_lock);
> +
> + *mask |= root->osc_control_set;
> + if ((ctrl & root->osc_control_set) == ctrl)
> + goto out;
> +
> + while (*mask && *mask != ctrl) {
> + ctrl = *mask;
> + status = acpi_pci_query_osc(root, root->osc_support_set, mask);
> + if (ACPI_FAILURE(status))
> + break;
> + }
> +
> + out:
> + mutex_unlock(&osc_lock);
> +
> + return status;
> +}
> +
> /**
> * acpi_pci_osc_control_set - commit requested control to Firmware
> * @handle: acpi_handle for the target ACPI object
> @@ -396,7 +449,7 @@ acpi_status acpi_pci_osc_control_set(acp
>
> /* Need to query controls first before requesting them */
> if (!root->osc_queried) {
> - status = acpi_pci_query_osc(root, root->osc_support_set);
> + status = acpi_pci_query_osc(root, root->osc_support_set, NULL);
> if (ACPI_FAILURE(status))
> goto out;
> }
> Index: linux-2.6/include/linux/acpi.h
> ===================================================================
> --- linux-2.6.orig/include/linux/acpi.h
> +++ linux-2.6/include/linux/acpi.h
> @@ -305,6 +305,7 @@ acpi_status acpi_run_osc(acpi_handle han
> OSC_PCI_EXPRESS_AER_CONTROL | \
> OSC_PCI_EXPRESS_CAP_STRUCTURE_CONTROL)
>
> +extern acpi_status acpi_pci_osc_control_query(acpi_handle handle, u32 *mask);
> extern acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 flags);
> extern void acpi_early_init(void);
>
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