Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754597AbYLHPST (ORCPT ); Mon, 8 Dec 2008 10:18:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754109AbYLHPRz (ORCPT ); Mon, 8 Dec 2008 10:17:55 -0500 Received: from ns2.suse.de ([195.135.220.15]:37066 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753183AbYLHPRy (ORCPT ); Mon, 8 Dec 2008 10:17:54 -0500 From: Thomas Renninger Organization: SUSE Linux - Novell To: Matthew Garrett Subject: Re: [PATCH] PCIe ASPM causes machine (HP Compaq 6735s) to sometimes freeze hard at boot at PCI initialization time Date: Mon, 8 Dec 2008 16:17:50 +0100 User-Agent: KMail/1.9.9 Cc: Shaohua Li , "linux-kernel@vger.kernel.org" , "jbarnes@virtuousgeek.org" , Rafael Wysocki , "shemminger@linux-foundation.org" , "netdev@vger.kernel.org" , "Stable@kernel.org" References: <200811281328.55259.trenn@suse.de> <200812081604.09996.trenn@suse.de> <20081208150919.GA1155@srcf.ucam.org> In-Reply-To: <20081208150919.GA1155@srcf.ucam.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200812081617.52047.trenn@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3298 Lines: 105 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 --- 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 #include #include +#include #include #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; /* * 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 */ + 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); + } } /* -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/