From a70b95c017e8b518e1e069853355e4e497453dbb Mon Sep 17 00:00:00 2001 From: Stephen Kitt Date: Mon, 31 Jan 2011 14:25:43 -0800 Subject: [PATCH] agp: ensure GART has an address before enabling it Some BIOSs (eg. the AMI BIOS on the Asus P4P800 motherboard) don't initialise the GART address, and pcibios_assign_resources() can ignore it because it can be marked as a host bridge (see https://bugzilla.kernel.org/show_bug.cgi?id=24392#c5 for details). This was handled correctly up to 2.6.35, but the pci_enable_device() cleanup in 2.6.36 96576a9e1a0cdb8 ("agp: intel-agp: do not use PCI resources before pci_enable_device()") means that the kernel tries to enable the GART before assigning it an address; in such cases the GART overlaps with other device assignments and ends up being disabled. This patch fixes https://bugzilla.kernel.org/show_bug.cgi?id=24392 Note that I imagine efficeon-agp.c probably has the same problem, but I can't test that and I'd like to make sure this patch is suitable for -stable (since 2.6.36 and 2.6.37 are affected). Signed-off-by: Stephen Kitt Cc: Bjorn Helgaas Cc: Maciej Rutecki Cc: "Rafael J. Wysocki" Cc: Kulikov Vasiliy Cc: Florian Mickler Cc: Signed-off-by: Andrew Morton Signed-off-by: Dave Airlie --- drivers/char/agp/intel-agp.c | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/drivers/char/agp/intel-agp.c b/drivers/char/agp/intel-agp.c index 857df10c0428..b0a0dccc98c1 100644 --- a/drivers/char/agp/intel-agp.c +++ b/drivers/char/agp/intel-agp.c @@ -773,21 +773,15 @@ static int __devinit agp_intel_probe(struct pci_dev *pdev, dev_info(&pdev->dev, "Intel %s Chipset\n", intel_agp_chipsets[i].name); - /* - * If the device has not been properly setup, the following will catch - * the problem and should stop the system from crashing. - * 20030610 - hamish@zot.org - */ - if (pci_enable_device(pdev)) { - dev_err(&pdev->dev, "can't enable PCI device\n"); - agp_put_bridge(bridge); - return -ENODEV; - } - /* * The following fixes the case where the BIOS has "forgotten" to * provide an address range for the GART. * 20030610 - hamish@zot.org + * This happens before pci_enable_device() intentionally; + * calling pci_enable_device() before assigning the resource + * will result in the GART being disabled on machines with such + * BIOSs (the GART ends up with a BAR starting at 0, which + * conflicts a lot of other devices). */ r = &pdev->resource[0]; if (!r->start && r->end) { @@ -798,6 +792,17 @@ static int __devinit agp_intel_probe(struct pci_dev *pdev, } } + /* + * If the device has not been properly setup, the following will catch + * the problem and should stop the system from crashing. + * 20030610 - hamish@zot.org + */ + if (pci_enable_device(pdev)) { + dev_err(&pdev->dev, "can't enable PCI device\n"); + agp_put_bridge(bridge); + return -ENODEV; + } + /* Fill in the mode register */ if (cap_ptr) { pci_read_config_dword(pdev, -- GitLab