Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757283Ab3C2WaI (ORCPT ); Fri, 29 Mar 2013 18:30:08 -0400 Received: from mail-ie0-f179.google.com ([209.85.223.179]:43203 "EHLO mail-ie0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756964Ab3C2WaG (ORCPT ); Fri, 29 Mar 2013 18:30:06 -0400 Date: Fri, 29 Mar 2013 16:30:02 -0600 From: Bjorn Helgaas To: Yinghai Lu Cc: Linus Torvalds , Andrew Morton , Matthew Whitehead , "linux-kernel@vger.kernel.org" , "stable@kernel.org" Subject: Re: [PATCH 1/2] eisa, PCI: Fix bus res reference Message-ID: <20130329223002.GA6740@google.com> References: <1364444885-19751-1-git-send-email-yinghai@kernel.org> <1364444885-19751-2-git-send-email-yinghai@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4410 Lines: 111 On Fri, Mar 29, 2013 at 12:10:37PM -0700, Yinghai Lu wrote: > On Fri, Mar 29, 2013 at 11:10 AM, Bjorn Helgaas wrote: > > On Wed, Mar 27, 2013 at 10:28 PM, Yinghai Lu wrote: > >> Matthem found that 3.8.3 is having problems with an old (ancient) > >> PCI-to-EISA bridge, the Intel 82375. It worked with the 3.2 kernel. > >> He identified the 82375, but doesn't assign the struct resource *res > >> pointer inside the struct eisa_root_device, and panics. > >> > >> After looking at pci_eisa_init(), found it referring bus resource > >> directly instead of pci_bus_resource_n(). > >> > >> After commit 45ca9e97 (PCI: add helpers for building PCI bus resource lists) > >> and commit 0efd5aab (PCI: add struct pci_host_bridge_window with CPU/bus > >> address offset), bus->resource[] is not used for pci root bus any more. > >> > >> Fix it by using pci_bus_resource_n() and correct idx for root bus. > >> > >> Reported-by: Matthew Whitehead > >> Tested-by: Matthew Whitehead > >> Signed-off-by: Yinghai Lu > >> Cc: stable@kernel.org > >> > >> --- > >> drivers/eisa/pci_eisa.c | 10 +++++++--- > >> 1 file changed, 7 insertions(+), 3 deletions(-) > >> > >> Index: linux-2.6/drivers/eisa/pci_eisa.c > >> =================================================================== > >> --- linux-2.6.orig/drivers/eisa/pci_eisa.c > >> +++ linux-2.6/drivers/eisa/pci_eisa.c > >> @@ -22,7 +22,8 @@ static struct eisa_root_device pci_eisa_ > >> static int __init pci_eisa_init(struct pci_dev *pdev, > >> const struct pci_device_id *ent) > >> { > >> - int rc; > >> + int rc, n = 0; > >> + struct resource *bus_res; > >> > >> if ((rc = pci_enable_device (pdev))) { > >> printk (KERN_ERR "pci_eisa : Could not enable device %s\n", > >> @@ -30,9 +31,12 @@ static int __init pci_eisa_init(struct p > >> return rc; > >> } > >> > >> + if (pci_is_root_bus(pdev->bus)) > >> + n = PCI_BRIDGE_RESOURCE_NUM; > >> + bus_res = pci_bus_resource_n(pdev->bus, n); > > > > I haven't figured out why the pci_is_root_bus() test is here. Can you > > explain, maybe with a sample dmesg log and "lspci -vvx" output? > > Just forwarded two boot.log. > > for root bus, pci_bus_resource_n[0, PCI_BRIDGE_RESOURCE_NUM) all > equal to 0. Thanks. The patch below is what I was thinking. That should work even in this scenario, I think, and it's nicer if we don't have to have this root bus internal knowledge here. diff --git a/drivers/eisa/pci_eisa.c b/drivers/eisa/pci_eisa.c index cdae207..3e9dee9 100644 --- a/drivers/eisa/pci_eisa.c +++ b/drivers/eisa/pci_eisa.c @@ -22,7 +22,8 @@ static struct eisa_root_device pci_eisa_root; static int __init pci_eisa_init(struct pci_dev *pdev, const struct pci_device_id *ent) { - int rc; + int rc, i; + struct resource *res; if ((rc = pci_enable_device (pdev))) { printk (KERN_ERR "pci_eisa : Could not enable device %s\n", @@ -30,9 +31,28 @@ static int __init pci_eisa_init(struct pci_dev *pdev, return rc; } + /* + * The Intel 82375 PCI-EISA bridge is a subtractive-decode PCI + * device, so the resources available on EISA are the same as those + * available on the 82375 bus. This works the same as a PCI-PCI + * bridge in subtractive-decode mode (see pci_read_bridge_bases()). + * We assume other PCI-EISA bridges are similar. + * + * eisa_root_register() can only deal with a single resource, so we + * use the first valid one. + */ + pci_bus_for_each_resource(pdev->bus, res, i) + if (res) + break; + + if (!res) { + dev_err(&pdev->dev, "No resources available\n"); + return -1; + } + pci_eisa_root.dev = &pdev->dev; - pci_eisa_root.res = pdev->bus->resource[0]; - pci_eisa_root.bus_base_addr = pdev->bus->resource[0]->start; + pci_eisa_root.res = res; + pci_eisa_root.bus_base_addr = res->start; pci_eisa_root.slots = EISA_MAX_SLOTS; pci_eisa_root.dma_mask = pdev->dma_mask; dev_set_drvdata(pci_eisa_root.dev, &pci_eisa_root); -- 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/