Messages in this thread Patch in this message |  | | | Date | Fri, 23 Mar 2012 17:20:53 +0000 | | From | Matthew Garrett <> | | Subject | Re: IDE DVD and CD drive seem to not work with Linux desktop 3.3.0-030300-generic |
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Ok, this is very odd - ASPM is disabled in both cases. The only thing I can think of here is that the hardware dislikes us writing to the registers? Can you test this patch on top of the broken kernel?
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c index 24f049e..04eb680 100644 --- a/drivers/pci/pcie/aspm.c +++ b/drivers/pci/pcie/aspm.c @@ -185,6 +185,7 @@ static void pcie_aspm_configure_common_clock(struct pcie_link_state *link) int ppos, cpos, same_clock = 1; u16 reg16, parent_reg, child_reg[8]; unsigned long start_jiffies; + bool retrain = false; struct pci_dev *child, *parent = link->pdev; struct pci_bus *linkbus = parent->subordinate; /* @@ -215,7 +216,10 @@ static void pcie_aspm_configure_common_clock(struct pcie_link_state *link) reg16 |= PCI_EXP_LNKCTL_CCC; else reg16 &= ~PCI_EXP_LNKCTL_CCC; - pci_write_config_word(child, cpos + PCI_EXP_LNKCTL, reg16); + if (reg16 != child_reg[PCI_FUNC(child->devfn)]) { + retrain = true; + pci_write_config_word(child, cpos + PCI_EXP_LNKCTL, reg16); + } } /* Configure upstream component */ @@ -225,9 +229,15 @@ static void pcie_aspm_configure_common_clock(struct pcie_link_state *link) reg16 |= PCI_EXP_LNKCTL_CCC; else reg16 &= ~PCI_EXP_LNKCTL_CCC; - pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, reg16); + if (reg16 != parent_reg) { + retrain = true; + pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, reg16); + } /* Retrain link */ + if (!retrain) + return; + reg16 |= PCI_EXP_LNKCTL_RL; pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, reg16); @@ -436,13 +446,16 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist) static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val) { - u16 reg16; + u16 reg16, orig_reg16; int pos = pci_pcie_cap(pdev); pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, ®16); + orig_reg16 = reg16; reg16 &= ~0x3; reg16 |= val; - pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16); + + if (reg16 != orig_reg16) + pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16); } static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state) -- Matthew Garrett | mjg59@srcf.ucam.org
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