145 lines
4.9 KiB
Diff
145 lines
4.9 KiB
Diff
From linux-kernel-owner@vger.kernel.org Mon Dec 6 14:01:17 2010
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From: Matthew Garrett <mjg@redhat.com>
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To: linux-pci@vger.kernel.org
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Cc: linux-kernel@vger.kernel.org, jbarnes@virtuousgeek.org,
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Matthew Garrett <mjg@redhat.com>
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Subject: [PATCH v2] PCI: Disable ASPM if BIOS asks us to
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Date: Mon, 6 Dec 2010 14:00:56 -0500
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Message-Id: <1291662056-6055-1-git-send-email-mjg@redhat.com>
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We currently refuse to touch the ASPM registers if the BIOS tells us that
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ASPM isn't supported. This can cause problems if the BIOS has (for any
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reason) enabled ASPM on some devices anyway. Change the code such that we
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explicitly clear ASPM if the FADT indicates that ASPM isn't supported,
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and make sure we tidy up appropriately on device removal in order to deal
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with the hotplug case. If ASPM is disabled because the BIOS doesn't hand
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over control then we won't touch the registers.
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Signed-off-by: Matthew Garrett <mjg@redhat.com>
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---
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Implement Rafael's suggestion to use two separate functions, and also
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ensure that we clear the clkpm bit as well as the ASPM bits.
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drivers/pci/pci-acpi.c | 1 +
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drivers/pci/pcie/aspm.c | 21 +++++++++++++++++----
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include/linux/pci-aspm.h | 5 ++++-
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3 files changed, 22 insertions(+), 5 deletions(-)
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diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
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index 24e19c5..d7ea699 100644
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--- a/drivers/pci/pci-acpi.c
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+++ b/drivers/pci/pci-acpi.c
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@@ -399,6 +399,7 @@ static int __init acpi_pci_init(void)
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if (acpi_gbl_FADT.boot_flags & ACPI_FADT_NO_ASPM) {
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printk(KERN_INFO"ACPI FADT declares the system doesn't support PCIe ASPM, so disable it\n");
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+ pcie_clear_aspm();
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pcie_no_aspm();
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}
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diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
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index 7122281..8112415 100644
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--- a/drivers/pci/pcie/aspm.c
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+++ b/drivers/pci/pcie/aspm.c
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@@ -68,7 +68,7 @@ struct pcie_link_state {
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struct aspm_latency acceptable[8];
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};
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-static int aspm_disabled, aspm_force;
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+static int aspm_disabled, aspm_force, aspm_clear_state;
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static DEFINE_MUTEX(aspm_lock);
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static LIST_HEAD(link_list);
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@@ -139,7 +139,7 @@ static void pcie_set_clkpm(struct pcie_link_state *link, int enable)
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{
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/* Don't enable Clock PM if the link is not Clock PM capable */
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if (!link->clkpm_capable && enable)
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- return;
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+ enable = 0;
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/* Need nothing if the specified equals to current state */
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if (link->clkpm_enabled == enable)
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return;
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@@ -498,6 +498,10 @@ static int pcie_aspm_sanity_check(struct pci_dev *pdev)
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struct pci_dev *child;
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int pos;
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u32 reg32;
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+
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+ if (aspm_clear_state)
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+ return -EINVAL;
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+
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/*
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* Some functions in a slot might not all be PCIe functions,
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* very strange. Disable ASPM for the whole slot
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@@ -563,12 +567,15 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
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struct pcie_link_state *link;
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int blacklist = !!pcie_aspm_sanity_check(pdev);
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- if (aspm_disabled || !pci_is_pcie(pdev) || pdev->link_state)
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+ if (!pci_is_pcie(pdev) || pdev->link_state)
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return;
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if (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
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pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM)
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return;
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+ if (aspm_disabled && !aspm_clear_state)
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+ return;
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+
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/* VIA has a strange chipset, root port is under a bridge */
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if (pdev->pcie_type == PCI_EXP_TYPE_ROOT_PORT &&
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pdev->bus->self)
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@@ -641,7 +648,7 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev)
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struct pci_dev *parent = pdev->bus->self;
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struct pcie_link_state *link, *root, *parent_link;
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- if (aspm_disabled || !pci_is_pcie(pdev) ||
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+ if ((aspm_disabled && !aspm_clear_state) || !pci_is_pcie(pdev) ||
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!parent || !parent->link_state)
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return;
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if ((parent->pcie_type != PCI_EXP_TYPE_ROOT_PORT) &&
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@@ -899,6 +906,12 @@ static int __init pcie_aspm_disable(char *str)
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__setup("pcie_aspm=", pcie_aspm_disable);
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+void pcie_clear_aspm(void)
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+{
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+ if (!aspm_force)
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+ aspm_clear_state = 1;
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+}
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+
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void pcie_no_aspm(void)
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{
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if (!aspm_force)
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diff --git a/include/linux/pci-aspm.h b/include/linux/pci-aspm.h
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index 91ba0b3..ce68105 100644
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--- a/include/linux/pci-aspm.h
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+++ b/include/linux/pci-aspm.h
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@@ -27,6 +27,7 @@ extern void pcie_aspm_init_link_state(struct pci_dev *pdev);
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extern void pcie_aspm_exit_link_state(struct pci_dev *pdev);
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extern void pcie_aspm_pm_state_change(struct pci_dev *pdev);
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extern void pci_disable_link_state(struct pci_dev *pdev, int state);
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+extern void pcie_clear_aspm(void);
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extern void pcie_no_aspm(void);
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#else
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static inline void pcie_aspm_init_link_state(struct pci_dev *pdev)
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@@ -41,7 +42,9 @@ static inline void pcie_aspm_pm_state_change(struct pci_dev *pdev)
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static inline void pci_disable_link_state(struct pci_dev *pdev, int state)
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{
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}
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-
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+static inline void pcie_clear_aspm(void)
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+{
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+}
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static inline void pcie_no_aspm(void)
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{
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}
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--
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1.7.3.2
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--
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