From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Sinan Kaya To: linux-pci@vger.kernel.org Cc: Sinan Kaya , Bjorn Helgaas , "Rafael J. Wysocki" , Len Brown , linux-acpi@vger.kernel.org (open list:ACPI), linux-kernel@vger.kernel.org (open list) Subject: [PATCH 2/2] PCI/ACPI: allow _OSC presence to be optional for PCI Date: Thu, 9 Aug 2018 18:46:23 +0000 Message-Id: <1533840383-7841-2-git-send-email-okaya@kernel.org> In-Reply-To: <1533840383-7841-1-git-send-email-okaya@kernel.org> References: <1533840383-7841-1-git-send-email-okaya@kernel.org> Sender: linux-acpi-owner@vger.kernel.org List-ID: 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 Reported-by: Michael Kelley --- drivers/acpi/pci_root.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c index 9d738e2..c94ed01 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; @@ -460,9 +461,14 @@ static void negotiate_os_control(struct acpi_pci_root *root, int *no_aspm) if (pcie_aspm_support_enabled()) aspm_msg = "; disabling ASPM"; - dev_info(&device->dev, "_OSC failed (%s) %s\n", - acpi_format_exception(status), aspm_msg); *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), aspm_msg); return; } @@ -538,6 +544,7 @@ 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) @@ -595,7 +602,8 @@ 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