From 2a42d9dba7842422ffb2c02e75288a8bc2fd5065 Mon Sep 17 00:00:00 2001 From: Thomas Renninger Date: Tue, 9 Dec 2008 13:05:09 +0100 Subject: [PATCH] PCIe: ASPM: Break out of endless loop waiting for PCI config bits to switch Makes a Compaq 6735s boot reliably again. It used to hang in the loop on some boots. Give the link one second to train, otherwise break out of the loop and reset the previously set clock bits. Cc: stable@vger.kernel.org Signed-off-by: Thomas Renninger Signed-off-by: Shaohua Li Signed-off-by: Matthew Garrett Signed-off-by: Jesse Barnes --- drivers/pci/pcie/aspm.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 8f63f4c..9aad608 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include "../pci.h" @@ -161,11 +162,12 @@ static void pcie_check_clock_pm(struct pci_dev *pdev) */ static void pcie_aspm_configure_common_clock(struct pci_dev *pdev) { - int pos, child_pos; + int pos, child_pos, i = 0; u16 reg16 = 0; struct pci_dev *child_dev; int same_clock = 1; - + unsigned long start_jiffies; + u16 child_regs[8], parent_reg; /* * all functions of a slot should have the same Slot Clock * Configuration, so just check one function @@ -191,16 +193,19 @@ static void pcie_aspm_configure_common_clock(struct pci_dev *pdev) child_pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP); pci_read_config_word(child_dev, child_pos + PCI_EXP_LNKCTL, ®16); + child_regs[i] = reg16; if (same_clock) reg16 |= PCI_EXP_LNKCTL_CCC; else reg16 &= ~PCI_EXP_LNKCTL_CCC; pci_write_config_word(child_dev, child_pos + PCI_EXP_LNKCTL, reg16); + i++; } /* Configure upstream component */ pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, ®16); + parent_reg = reg16; if (same_clock) reg16 |= PCI_EXP_LNKCTL_CCC; else @@ -212,12 +217,30 @@ static void pcie_aspm_configure_common_clock(struct pci_dev *pdev) pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16); /* Wait for link training end */ - while (1) { + /* break out after waiting for 1 second */ + start_jiffies = jiffies; + while ((jiffies - start_jiffies) < HZ) { pci_read_config_word(pdev, pos + PCI_EXP_LNKSTA, ®16); if (!(reg16 & PCI_EXP_LNKSTA_LT)) break; cpu_relax(); } + /* training failed -> recover */ + if ((jiffies - start_jiffies) >= HZ) { + dev_printk (KERN_ERR, &pdev->dev, "ASPM: Could not configure" + " common clock\n"); + i = 0; + list_for_each_entry(child_dev, &pdev->subordinate->devices, + bus_list) { + child_pos = pci_find_capability(child_dev, + PCI_CAP_ID_EXP); + pci_write_config_word(child_dev, + child_pos + PCI_EXP_LNKCTL, + child_regs[i]); + i++; + } + pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, parent_reg); + } } /* -- 2.7.4