From: Ralf Baechle Since commit 368c73d4f689dae0807d0a2aa74c61fd2b9b075f the kernel will try to update the non-writeable BAR registers 0..3 of PIIX4 IDE adapters if pci_assign_unassigned_resources() is used to do full resource assignment of the bus. This fails because in the PIIX4 these BAR registers have implicitly assumed values and read back as zero; it used to work because the kernel used to just write zero to that register the read back value did match what was written. The fix is a new resource flag IORESOURCE_PCI_FIXED used to mark a resource as non-movable. This will also be useful to keep other import system resources from being moved around - for example system consoles on PCI busses. Signed-off-by: Ralf Baechle Acked-by: Alan Cox Cc: Greg KH Signed-off-by: Andrew Morton --- drivers/pci/probe.c | 11 +++++++---- drivers/pci/setup-res.c | 11 +++++++++++ include/linux/ioport.h | 3 +++ 3 files changed, 21 insertions(+), 4 deletions(-) diff -puN drivers/pci/probe.c~pci-legacy-resource-fix drivers/pci/probe.c --- a/drivers/pci/probe.c~pci-legacy-resource-fix +++ a/drivers/pci/probe.c @@ -692,6 +692,9 @@ static void pci_read_irq(struct pci_dev * Returns 0 on success and -1 if unknown type of device (not normal, bridge * or CardBus). */ + +#define LEGACY_IO_RESOURCE (IORESOURCE_IO | IORESOURCE_PCI_FIXED) + static int pci_setup_device(struct pci_dev * dev) { u32 class; @@ -735,18 +738,18 @@ static int pci_setup_device(struct pci_d if ((progif & 1) == 0) { dev->resource[0].start = 0x1F0; dev->resource[0].end = 0x1F7; - dev->resource[0].flags = IORESOURCE_IO; + dev->resource[0].flags = LEGACY_IO_RESOURCE; dev->resource[1].start = 0x3F6; dev->resource[1].end = 0x3F6; - dev->resource[1].flags = IORESOURCE_IO; + dev->resource[1].flags = LEGACY_IO_RESOURCE; } if ((progif & 4) == 0) { dev->resource[2].start = 0x170; dev->resource[2].end = 0x177; - dev->resource[2].flags = IORESOURCE_IO; + dev->resource[2].flags = LEGACY_IO_RESOURCE; dev->resource[3].start = 0x376; dev->resource[3].end = 0x376; - dev->resource[3].flags = IORESOURCE_IO; + dev->resource[3].flags = LEGACY_IO_RESOURCE; } } break; diff -puN drivers/pci/setup-res.c~pci-legacy-resource-fix drivers/pci/setup-res.c --- a/drivers/pci/setup-res.c~pci-legacy-resource-fix +++ a/drivers/pci/setup-res.c @@ -38,6 +38,13 @@ pci_update_resource(struct pci_dev *dev, if (!res->flags) return; + /* Ignore non-moveable resources. This might be legacy resources for + which no functional BAR register exists or another important + system resource we should better not move around in system address + space. */ + if (res->flags & IORESOURCE_PCI_FIXED) + return; + pcibios_resource_to_bus(dev, ®ion, res); pr_debug(" got res [%llx:%llx] bus [%lx:%lx] flags %lx for " @@ -212,6 +219,10 @@ pdev_sort_resources(struct pci_dev *dev, resource_size_t r_align; r = &dev->resource[i]; + + if (r->flags & IORESOURCE_PCI_FIXED) + continue; + r_align = r->end - r->start; if (!(r->flags) || r->parent) diff -puN include/linux/ioport.h~pci-legacy-resource-fix include/linux/ioport.h --- a/include/linux/ioport.h~pci-legacy-resource-fix +++ a/include/linux/ioport.h @@ -91,6 +91,9 @@ struct resource_list { #define IORESOURCE_ROM_COPY (1<<2) /* ROM is alloc'd copy, resource field overlaid */ #define IORESOURCE_ROM_BIOS_COPY (1<<3) /* ROM is BIOS copy, resource field overlaid */ +/* PCI control bits. Shares IORESOURCE_BITS with above PCI ROM. */ +#define IORESOURCE_PCI_FIXED (1<<4) /* Do not move resource */ + /* PC/ISA/whatever - the normal PC address spaces: IO and memory */ extern struct resource ioport_resource; extern struct resource iomem_resource; _