From 16d917b130d782b94fa02afc7bdf0d4aae689da4 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Tue, 8 Nov 2016 14:25:24 -0600 Subject: [PATCH] PCI: Don't attempt to claim shadow copies of ROM If we're using a shadow copy of a PCI device ROM, the shadow copy is in RAM and the device never sees accesses to it and doesn't respond to it. We don't have to route the shadow range to the PCI device, and the device doesn't have to claim the range. Previously we treated the shadow copy as though it were the ROM BAR, and we failed to claim it because the region wasn't routed to the device: pci 0000:01:00.0: Video device with shadowed ROM at [mem 0x000c0000-0x000dffff] pci_bus 0000:01: Allocating resources pci 0000:01:00.0: can't claim BAR 6 [mem 0x000c0000-0x000dffff]: no compatible bridge window The failure path of pcibios_allocate_dev_rom_resource() cleared out the resource start address, which also caused the following ioremap() warning: WARNING: CPU: 0 PID: 116 at /build/linux-akdJXO/linux-4.8.0/arch/x86/mm/ioremap.c:121 __ioremap_caller+0x1ec/0x370 ioremap on RAM at 0x0000000000000000 - 0x000000000001ffff Handle an option ROM shadow copy as RAM, without trying to insert it into the iomem resource tree. This fixes a regression caused by 0c0e0736acad ("PCI: Set ROM shadow location in arch code, not in PCI core"), which appeared in v4.6. The regression causes video device initialization to fail. This was reported on AMD Turks, but it likely affects others as well. Fixes: 0c0e0736acad ("PCI: Set ROM shadow location in arch code, not in PCI core") Reported-and-tested-by: Vecu Bosseur Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1627496 Link: https://bugzilla.kernel.org/show_bug.cgi?id=175391 Link: https://bugzilla.redhat.com/show_bug.cgi?id=1352272 Signed-off-by: Bjorn Helgaas CC: stable@vger.kernel.org # v4.6+ --- drivers/pci/setup-res.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c index 66c4d8f42233..9526e341988b 100644 --- a/drivers/pci/setup-res.c +++ b/drivers/pci/setup-res.c @@ -121,6 +121,14 @@ int pci_claim_resource(struct pci_dev *dev, int resource) return -EINVAL; } + /* + * If we have a shadow copy in RAM, the PCI device doesn't respond + * to the shadow range, so we don't need to claim it, and upstream + * bridges don't need to route the range to the device. + */ + if (res->flags & IORESOURCE_ROM_SHADOW) + return 0; + root = pci_find_parent_resource(dev, res); if (!root) { dev_info(&dev->dev, "can't claim BAR %d %pR: no compatible bridge window\n", -- 2.20.1