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Date: Tue, 09 Dec 2008 09:19:39 +0800 From: Shaohua Li <shaohua.li@...el.com> To: Thomas Renninger <trenn@...e.de> Cc: Matthew Garrett <mjg59@...f.ucam.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "jbarnes@...tuousgeek.org" <jbarnes@...tuousgeek.org>, Rafael Wysocki <rwysocki@...e.de>, "shemminger@...ux-foundation.org" <shemminger@...ux-foundation.org>, "netdev@...r.kernel.org" <netdev@...r.kernel.org>, "Stable@...nel.org" <Stable@...nel.org> Subject: Re: [PATCH] PCIe ASPM causes machine (HP Compaq 6735s) to sometimes freeze hard at boot at PCI initialization time On Mon, 2008-12-08 at 23:17 +0800, Thomas Renninger wrote: > On Monday 08 December 2008 16:09:19 Matthew Garrett wrote: > > On Mon, Dec 08, 2008 at 04:04:09PM +0100, Thomas Renninger wrote: > > > - pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, ®16); > > > + parent_reg = pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, ®16); > > > > I don't think that does what you think it does :) > > Hehe, thanks for the quick and detailed review! > > This one should be better: > > PCIe: ASPM: Break out of endless loop waiting for PCI config bits to switch > > Makes a Compaq 6735s boot reliably again which hang in the loop > on some boots. > > Signed-off-by: Thomas Renninger <trenn@...e.de> > > --- > drivers/pci/pcie/aspm.c | 28 +++++++++++++++++++++++++--- > 1 file changed, 25 insertions(+), 3 deletions(-) > > Index: linux-2.6.27/drivers/pci/pcie/aspm.c > =================================================================== > --- linux-2.6.27.orig/drivers/pci/pcie/aspm.c > +++ linux-2.6.27/drivers/pci/pcie/aspm.c > @@ -16,6 +16,7 @@ > #include <linux/pm.h> > #include <linux/init.h> > #include <linux/slab.h> > +#include <linux/jiffies.h> > #include <linux/pci-aspm.h> > #include "../pci.h" > > @@ -161,11 +162,12 @@ static void pcie_check_clock_pm(struct p > */ > 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 = jiffies; > + u16 child_regs[256], parent_reg; child_regs[8] should be enough. There should be just one pcie slot under the port. > /* > * 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_c > 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 +217,29 @@ static void pcie_aspm_configure_common_c > pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16); > > /* Wait for link training end */ > - while (1) { > + /* break out after waiting for 1 second */ should we set start_jiffies here? Otherwise, it's ok to me. Thanks, Shaohua -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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