Re: [PATCH 2/7] ACPI / PCI: Introduce acpi_pci_root_osc_query()

From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: linux-pci@vger.kernel.org,
	Jesse Barnes <jbarnes@virtuousgeek.org>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>,
	linux-pm@lists.linux-foundation.org
Subject: Re: [PATCH 2/7] ACPI / PCI: Introduce acpi_pci_root_osc_query()
Date: Mon, 2 Aug 2010 16:13:38 +0200	[thread overview]
Message-ID: <201008021613.38498.rjw__15192.6606348299$1280758874$gmane$org@sisk.pl> (raw)
In-Reply-To: <4C568D7F.5080105@jp.fujitsu.com>

On Monday, August 02, 2010, Hidetoshi Seto wrote:
> (2010/07/31 7:26), Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rjw@sisk.pl>
> > 
> > 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@sisk.pl>
> > ---
> >  drivers/acpi/pci_root.c |   56 +++++++++++++++++++++++++++++++++++++++++-------
> >  include/linux/acpi.h    |    1 
> >  2 files changed, 49 insertions(+), 8 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
> > @@ -224,21 +224,32 @@ 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, capbuf[3];
> > +	u32 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;
> > +	} else {
> > +		capbuf[OSC_CONTROL_TYPE] = OSC_PCI_CONTROL_MASKS;
> > +	}
> >  
> >  	status = acpi_pci_run_osc(root->device->handle, capbuf);
> >  	if (ACPI_SUCCESS(status)) {
> > -		root->osc_support_set = support_set;
> > +		root->osc_support_set = support;
> >  		root->osc_control_qry = capbuf[OSC_CONTROL_TYPE];
> > +		if (control)
> > +			*control = capbuf[OSC_CONTROL_TYPE];
> >  		root->osc_queried = 1;
> >  	}
> >  	return status;
> > @@ -253,7 +264,7 @@ 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;
> >  }
> > @@ -362,6 +373,35 @@ out:
> >  }
> >  EXPORT_SYMBOL_GPL(acpi_get_pci_dev);
> >  
> > + /**
> > + * acpi_pci_root_osc_query - Get the _OSC bits the kernel can control.
> > + * @handle: ACPI handle of a PCI root bridge (or PCIe Root Complex).
> > + * @ctrl_mask: Mask of _OSC bits to query and the place to put the result into.
> > + **/
> > +acpi_status acpi_pci_root_osc_query(acpi_handle handle, u32 *ctrl_mask)
> > +{
> > +	acpi_status status;
> > +	acpi_handle tmp;
> > +	struct acpi_pci_root *root;
> > +
> > +	if (!ctrl_mask || !(*ctrl_mask & 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);
> > +	status = acpi_pci_query_osc(root, root->osc_support_set, ctrl_mask);
> > +	mutex_unlock(&osc_lock);
> > +
> > +	return status;
> > +}
> > +
> >  /**
> >   * acpi_pci_osc_control_set - commit requested control to Firmware
> >   * @handle: acpi_handle for the target ACPI object
> > @@ -395,7 +435,7 @@ 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_root_osc_query(acpi_handle handle, u32 *ctrl_mask);
> >  extern acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 flags);
> >  extern void acpi_early_init(void);
> 
> IMHO acpi_pci_osc_control_query() is better name for new function here,
> to make it be paired with acpi_pci_osc_control_set(), and to avoid mistakable
> "*_get" that sounds like it takes controls via _OSC.

OK, I'll change that, but IMHO we're entering the "splitting hairs" area here. :-)

Thanks,
Rafael