Commit 6bc779ee authored by Joerg Roedel's avatar Joerg Roedel Committed by Bjorn Helgaas
Browse files

PCI/ACPI: Check for _OSC support in acpi_pci_osc_control_set() 

Get rid of acpi_pci_osc_support() and check for _OSC supported features
directly in acpi_pci_osc_control_set(). There is no point in doing an
unconditional _OSC query with control=0 even when the kernel later wants to
take control over more features.

This saves one _OSC query and simplifies the code by getting rid of the
acpi_pci_osc_support() function. As a side effect, the !control checks in
acpi_pci_query_osc() can also be removed.

Link: https://lore.kernel.org/r/20210824122054.29481-5-joro@8bytes.org


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: default avatarRafael J. Wysocki <rafael@kernel.org>
parent 87f1f87a

drivers/acpi/pci_root.c

+32 −49
Original line number Diff line number Diff line
@@ -203,26 +203,16 @@ static acpi_status acpi_pci_query_osc(struct acpi_pci_root *root, 


	capbuf[OSC_QUERY_DWORD] = OSC_QUERY_ENABLE;

	capbuf[OSC_SUPPORT_DWORD] = support;

	if (control)

	capbuf[OSC_CONTROL_DWORD] = *control | root->osc_control_set;

	else

		/* Run _OSC query only with existing controls. */

		capbuf[OSC_CONTROL_DWORD] = root->osc_control_set;



	status = acpi_pci_run_osc(root->device->handle, capbuf, &result);

	if (ACPI_SUCCESS(status)) {

		root->osc_support_set = support;

		if (control)

		*control = result;

	}

	return status;

}



static acpi_status acpi_pci_osc_support(struct acpi_pci_root *root, u32 flags)

{

	return acpi_pci_query_osc(root, flags, NULL);

}



struct acpi_pci_root *acpi_pci_find_root(acpi_handle handle)

{

	struct acpi_pci_root *root;
@@ -345,8 +335,9 @@ EXPORT_SYMBOL_GPL(acpi_get_pci_dev); 
 * _OSC bits the BIOS has granted control of, but its contents are meaningless

 * on failure.

 **/

static acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req)

static acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 support)

{

	u32 req = OSC_PCI_EXPRESS_CAPABILITY_CONTROL;

	struct acpi_pci_root *root;

	acpi_status status;

	u32 ctrl, capbuf[3];
@@ -354,22 +345,16 @@ static acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 r 
	if (!mask)

		return AE_BAD_PARAMETER;



	ctrl = *mask;

	if ((ctrl & req) != req)

		return AE_TYPE;



	root = acpi_pci_find_root(handle);

	if (!root)

		return AE_NOT_EXIST;



	*mask = ctrl | root->osc_control_set;

	/* No need to evaluate _OSC if the control was already granted. */

	if ((root->osc_control_set & ctrl) == ctrl)

		return AE_OK;

	ctrl   = *mask;

	*mask |= root->osc_control_set;



	/* Need to check the available controls bits before requesting them. */

	while (*mask) {

		status = acpi_pci_query_osc(root, root->osc_support_set, mask);

	do {

		status = acpi_pci_query_osc(root, support, mask);

		if (ACPI_FAILURE(status))

			return status;

		if (ctrl == *mask)
@@ -377,7 +362,11 @@ static acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 r 
		decode_osc_control(root, "platform does not support",

				   ctrl & ~(*mask));

		ctrl = *mask;

	}

	} while (*mask);



	/* No need to request _OSC if the control was already granted. */

	if ((root->osc_control_set & ctrl) == ctrl)

		return AE_OK;



	if ((ctrl & req) != req) {

		decode_osc_control(root, "not requesting control; platform does not support",
@@ -470,7 +459,7 @@ static bool os_control_query_checks(struct acpi_pci_root *root, u32 support) 
static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,

				 bool is_pcie)

{

	u32 support, control, requested;

	u32 support, control = 0, requested = 0;

	acpi_status status;

	struct acpi_device *device = root->device;

	acpi_handle handle = device->handle;
@@ -490,28 +479,15 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm, 
	support = calculate_support();



	decode_osc_support(root, "OS supports", support);

	status = acpi_pci_osc_support(root, support);

	if (ACPI_FAILURE(status)) {

		*no_aspm = 1;



		/* _OSC is optional for PCI host bridges */

		if ((status == AE_NOT_FOUND) && !is_pcie)

			return;



		dev_info(&device->dev, "_OSC: platform retains control of PCIe features (%s)\n",

			 acpi_format_exception(status));

		return;

	}



	if (!os_control_query_checks(root, support))

		return;



	if (os_control_query_checks(root, support))

		requested = control = calculate_control();



	status = acpi_pci_osc_control_set(handle, &control,

					  OSC_PCI_EXPRESS_CAPABILITY_CONTROL);

	status = acpi_pci_osc_control_set(handle, &control, support);

	if (ACPI_SUCCESS(status)) {

		if (control)

			decode_osc_control(root, "OS now controls", control);



		if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {

			/*

			 * We have ASPM control, but the FADT indicates that
@@ -522,11 +498,6 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm, 
			*no_aspm = 1;

		}

	} else {

		decode_osc_control(root, "OS requested", requested);

		decode_osc_control(root, "platform willing to grant", control);

		dev_info(&device->dev, "_OSC: platform retains control of PCIe features (%s)\n",

			acpi_format_exception(status));



		/*

		 * We want to disable ASPM here, but aspm_disabled

		 * needs to remain in its state from boot so that we
@@ -535,6 +506,18 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm, 
		 * root scan.

		 */

		*no_aspm = 1;



		/* _OSC is optional for PCI host bridges */

		if ((status == AE_NOT_FOUND) && !is_pcie)

			return;



		if (control) {

			decode_osc_control(root, "OS requested", requested);

			decode_osc_control(root, "platform willing to grant", control);

		}



		dev_info(&device->dev, "_OSC: platform retains control of PCIe features (%s)\n",

			 acpi_format_exception(status));

	}

}