With DEBUG in arch/powerpc/kernel/pci-common.c, debug in commandline and a patch with some printk's (I attached the patch because it is the usual "put printk's everywhere" so the diff helps to understand where the prints come from). Corrected prinf format specifiers according to the comments from Sergei Shtylyov. PCI host bridge /plb/pci@1ec000000 (primary) ranges: MEM 0x0000000180000000..0x000000018fffffff -> 0x0000000080000000 IO 0x00000001e8000000..0x00000001e80fffff -> 0x0000000000000000 4xx PCI DMA offset set to 0x00000000 PCI: Probing PCI hardware PCI: Hiding 4xx host bridge resources 0000:00:00.0 Try to map irq for 0000:00:00.0... -> got one, spec 2 cells (0x00000003 0x00000008...) on /interrupt-controller2 -> mapped to linux irq 16 Try to map irq for 0000:00:0a.0... -> got one, spec 2 cells (0x00000003 0x00000008...) on /interrupt-controller2 -> mapped to linux irq 16 Try to map irq for 0000:00:0a.1... PCI: PHB (bus 0) bridge rsrc 0: 0000000000000000-00000000000fffff [0x100], parent c0365060 (PCI IO) __request_resource - request 0xcf8045b0 name '/plb/pci@1ec000000' start 0x0 end 0xfffff __request_resource - no conflict parent 0xc0365060 sibling 0x00000000 PCI: PHB (bus 0) bridge rsrc 1: 0000000180000000-000000018fffffff [0x200], parent c0365038 (PCI mem) __request_resource - request 0xcf8045d8 name '/plb/pci@1ec000000' start 0x180000000 end 0x18fffffff __request_resource - no conflict parent 0xc0365038 sibling 0x00000000 PCI: Assigning unassigned resouces... pci_assign_unassigned_resources -#1- bus 0xcf82d400 pci_assign_unassigned_resources -#2- bus 0xcf82d400 pci_assign_resource - allocate with IORESOURCE_PREFETCH pci_bus_alloc_resource - enter pci_assign_resource - second pci_bus_alloc_resource call pci_bus_alloc_resource - enter pci_bus_alloc_resource - call allocate ressource size 0x8000000 startcalc 0xffffffff, align 0x8000000 find_resource - size 0x8000000, min 0x180000000, max 0xffffffffffffffff find_resource - found start 0x180000000 end 0x187ffffff __request_resource - request 0xcf810578 name '0000:00:0a.0' start 0x180000000 end 0x187ffffff __request_resource - no conflict parent 0xcf8045d8 sibling 0x00000000 pci_assign_resource - allocate with IORESOURCE_PREFETCH pci_bus_alloc_resource - enter pci_assign_resource - second pci_bus_alloc_resource call pci_bus_alloc_resource - enter pci_bus_alloc_resource - call allocate ressource size 0x8000000 startcalc 0xffffffff, align 0x8000000 find_resource - size 0x8000000, min 0x180000000, max 0xffffffffffffffff find_resource - continue with start 0x188000000 on 0x00000000 find_resource - found start 0x188000000 end 0x18fffffff __request_resource - request 0xcf810178 name '0000:00:0a.1' start 0x188000000 end 0x18fffffff __request_resource - no conflict parent 0xcf8045d8 sibling 0x00000000 pci_assign_resource - allocate with IORESOURCE_PREFETCH pci_bus_alloc_resource - enter pci_assign_resource - second pci_bus_alloc_resource call pci_bus_alloc_resource - enter pci_bus_alloc_resource - call allocate ressource size 0x20000 startcalc 0xffffffff, align 0x20000 find_resource - size 0x20000, min 0x180000000, max 0xffffffffffffffff find_resource - continue with start 0x188000000 on 0xcf810178 find_resource - continue with start 0x190000000 on 0x00000000 find_resource - no this - exit PCI: pci_assign_resource - Failed to allocate mem resource #6:20000@190000000 for 0000:00:0a.0 pci_assign_resource - allocate with IORESOURCE_PREFETCH pci_bus_alloc_resource - enter pci_bus_alloc_resource - call allocate ressource size 0x10000 startcalc 0xffffffff, align 0x10000 find_resource - size 0x10000, min 0x180000000, max 0xffffffffffffffff find_resource - continue with start 0x188000000 on 0xcf810178 find_resource - continue with start 0x190000000 on 0x00000000 find_resource - no this - exit PCI: pci_assign_resource - Failed to allocate mem resource #2:10000@190000000 for 0000:00:0a.0 pci_assign_resource - allocate with IORESOURCE_PREFETCH pci_bus_alloc_resource - enter pci_bus_alloc_resource - call allocate ressource size 0x10000 startcalc 0xffffffff, align 0x10000 find_resource - size 0x10000, min 0x180000000, max 0xffffffffffffffff find_resource - continue with start 0x188000000 on 0xcf810178 find_resource - continue with start 0x190000000 on 0x00000000 find_resource - no this - exit PCI: pci_assign_resource - Failed to allocate mem resource #1:10000@190000000 for 0000:00:0a.1 pci_assign_resource - allocate with IORESOURCE_PREFETCH pci_bus_alloc_resource - enter pci_bus_alloc_resource - call allocate ressource size 0x100 startcalc 0xffffffff, align 0x100 find_resource - size 0x100, min 0x1000, max 0xffffffffffffffff find_resource - found start 0x1000 end 0x10ff __request_resource - request 0xcf8105a0 name '0000:00:0a.0' start 0x1000 end 0x10ff __request_resource - no conflict parent 0xcf8045b0 sibling 0x00000000 [...] radeonfb_pci_register BEGIN radeonfb_pci_register - resource0 0x180000000 - 0x187ffffff radeonfb_pci_register - resource1 0x1000 - 0x10ff radeonfb_pci_register - resource2 0x0 - 0x0 radeonfb_pci_register - got pci ressources fb_base_phys 0x180000000 mmio_base_phys 0x0 __request_resource - request 0xcf8bfd20 name 'radeonfb framebuffer' start 0x180000000 end 0x187ffffff __request_resource - request 0xcf8bfd20 name 'radeonfb framebuffer' start 0x180000000 end 0x187ffffff __request_resource - request 0xcf8bfd20 name 'radeonfb framebuffer' start 0x180000000 end 0x187ffffff __request_resource - no conflict parent 0xcf810578 sibling 0x00000000 radeonfb_pci_register - call ioremap for base 0x0 and size 16384 __ioremap(): phys addr 0x0 is RAM lr 0xc029df88 - mem_init_done 1 highmem@0x10000000 radeonfb (0000:00:0a.0): cannot map MMIO radeonfb: probe of 0000:00:0a.0 failed with error -5