LKML Archive on lore.kernel.org
 help / Atom feed
* [PATCH v2 1/2] PCI/ACPI: correct error message for ASPM disabling
@ 2018-08-10  4:32 Sinan Kaya
  2018-08-10  4:32 ` [PATCH v2 2/2] PCI/ACPI: allow _OSC presence to be optional for PCI Sinan Kaya
  0 siblings, 1 reply; 2+ messages in thread
From: Sinan Kaya @ 2018-08-10  4:32 UTC (permalink / raw)
  To: linux-pci
  Cc: Sinan Kaya, Bjorn Helgaas, Rafael J. Wysocki, Len Brown,
	linux-acpi, linux-kernel

If _OSC execution fails today for platforms without an _OSC
entry, code is printing a misleading message saying disabling
ASPM as follows:

acpi PNP0A03:00: _OSC failed (AE_NOT_FOUND); disabling ASPM

We need to ensure that platform supports ASPM to begin with.

Signed-off-by: Sinan Kaya <okaya@kernel.org>
Reported-by: Michael Kelley <mikelley@microsoft.com>
---
 drivers/acpi/pci_root.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index 7433035..e465e72 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -455,8 +455,9 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
 	decode_osc_support(root, "OS supports", support);
 	status = acpi_pci_osc_support(root, support);
 	if (ACPI_FAILURE(status)) {
-		dev_info(&device->dev, "_OSC failed (%s); disabling ASPM\n",
-			 acpi_format_exception(status));
+		dev_info(&device->dev, "_OSC failed (%s)%s\n",
+			 acpi_format_exception(status),
+			 pcie_aspm_support_enabled() ? "; disabling ASPM" : "");
 		*no_aspm = 1;
 		return;
 	}
-- 
2.7.4


^ permalink raw reply	[flat|nested] 2+ messages in thread

* [PATCH v2 2/2] PCI/ACPI: allow _OSC presence to be optional for PCI
  2018-08-10  4:32 [PATCH v2 1/2] PCI/ACPI: correct error message for ASPM disabling Sinan Kaya
@ 2018-08-10  4:32 ` Sinan Kaya
  0 siblings, 0 replies; 2+ messages in thread
From: Sinan Kaya @ 2018-08-10  4:32 UTC (permalink / raw)
  To: linux-pci
  Cc: Sinan Kaya, Bjorn Helgaas, Rafael J. Wysocki, Len Brown,
	linux-acpi, linux-kernel

ACPI Spec 6.0 Section 6.2.11.3 OSC Implementation Example for PCI
Host Bridge Devices:

For a host bridge device that originates a PCI Express hierarchy,
the _OSC interface defined in this section is required.

For a host bridge device that originates a PCI/PCI-X bus hierarchy,
inclusion of an _OSC object is optional.

Allow PCI host bridges to bail out silently if _OSC is not found.

Signed-off-by: Sinan Kaya <okaya@kernel.org>
Reported-by: Michael Kelley <mikelley@microsoft.com>
---
 drivers/acpi/pci_root.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index e465e72..707aafc 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -421,7 +421,8 @@ acpi_status acpi_pci_osc_control_set(acpi_handle handle, u32 *mask, u32 req)
 }
 EXPORT_SYMBOL(acpi_pci_osc_control_set);
 
-static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
+static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm,
+				 bool is_pcie)
 {
 	u32 support, control, requested;
 	acpi_status status;
@@ -455,10 +456,15 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm)
 	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 failed (%s)%s\n",
 			 acpi_format_exception(status),
 			 pcie_aspm_support_enabled() ? "; disabling ASPM" : "");
-		*no_aspm = 1;
 		return;
 	}
 
@@ -534,6 +540,7 @@ static int acpi_pci_root_add(struct acpi_device *device,
 	acpi_handle handle = device->handle;
 	int no_aspm = 0;
 	bool hotadd = system_state == SYSTEM_RUNNING;
+	bool is_pcie;
 
 	root = kzalloc(sizeof(struct acpi_pci_root), GFP_KERNEL);
 	if (!root)
@@ -591,7 +598,8 @@ static int acpi_pci_root_add(struct acpi_device *device,
 
 	root->mcfg_addr = acpi_pci_root_get_mcfg_addr(handle);
 
-	negotiate_os_control(root, &no_aspm);
+	is_pcie = strcmp(acpi_device_hid(device), "PNP0A08") == 0;
+	negotiate_os_control(root, &no_aspm, is_pcie);
 
 	/*
 	 * TBD: Need PCI interface for enumeration/configuration of roots.
-- 
2.7.4


^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, back to index

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-08-10  4:32 [PATCH v2 1/2] PCI/ACPI: correct error message for ASPM disabling Sinan Kaya
2018-08-10  4:32 ` [PATCH v2 2/2] PCI/ACPI: allow _OSC presence to be optional for PCI Sinan Kaya

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org linux-kernel@archiver.kernel.org
	public-inbox-index lkml


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/ public-inbox