Revision 93d2175d3d31f11ba04fcfa0e9a496a1b4bc8b34 authored by Yinghai Lu on 14 May 2011, 01:06:17 UTC, committed by Linus Torvalds on 17 May 2011, 01:33:35 UTC
During pci remove/rescan testing found: pci 0000:c0:03.0: PCI bridge to [bus c4-c9] pci 0000:c0:03.0: bridge window [io 0x1000-0x0fff] pci 0000:c0:03.0: bridge window [mem 0xf0000000-0xf00fffff] pci 0000:c0:03.0: bridge window [mem 0xfc180000000-0xfc197ffffff 64bit pref] pci 0000:c0:03.0: device not available (can't reserve [io 0x1000-0x0fff]) pci 0000:c0:03.0: Error enabling bridge (-22), continuing pci 0000:c0:03.0: enabling bus mastering pci 0000:c0:03.0: setting latency timer to 64 pcieport 0000:c0:03.0: device not available (can't reserve [io 0x1000-0x0fff]) pcieport: probe of 0000:c0:03.0 failed with error -22 This bug was caused by commit c8adf9a3e873 ("PCI: pre-allocate additional resources to devices only after successful allocation of essential resources.") After that commit, pci_hotplug_io_size is changed to additional_io_size from minium size. So it will not go through resource_size(res) != 0 path, and will not be reset. The root cause is: pci_bridge_check_ranges will set RESOURCE_IO flag for pci bridge, and later if children do not need IO resource. those bridge resources will not need to be allocated. but flags is still there. that will confuse the the pci_enable_bridges later. related code: static void assign_requested_resources_sorted(struct resource_list *head, struct resource_list_x *fail_head) { struct resource *res; struct resource_list *list; int idx; for (list = head->next; list; list = list->next) { res = list->res; idx = res - &list->dev->resource[0]; if (resource_size(res) && pci_assign_resource(list->dev, idx)) { ... reset_resource(res); } } } At last, We have to clear the flags in pbus_size_mem/io when requested size == 0 and !add_head. becasue this case it will not go through adjust_resources_sorted(). Just make size1 = size0 when !add_head. it will make flags get cleared. At the same time when requested size == 0, add_size != 0, will still have in head and add_list. because we do not clear the flags for it. After this, we will get right result: pci 0000:c0:03.0: PCI bridge to [bus c4-c9] pci 0000:c0:03.0: bridge window [io disabled] pci 0000:c0:03.0: bridge window [mem 0xf0000000-0xf00fffff] pci 0000:c0:03.0: bridge window [mem 0xfc180000000-0xfc197ffffff 64bit pref] pci 0000:c0:03.0: enabling bus mastering pci 0000:c0:03.0: setting latency timer to 64 pcieport 0000:c0:03.0: setting latency timer to 64 pcieport 0000:c0:03.0: irq 160 for MSI/MSI-X pcieport 0000:c0:03.0: Signaling PME through PCIe PME interrupt pci 0000:c4:00.0: Signaling PME through PCIe PME interrupt pcie_pme 0000:c0:03.0:pcie01: service driver pcie_pme loaded aer 0000:c0:03.0:pcie02: service driver aer loaded pciehp 0000:c0:03.0:pcie04: Hotplug Controller: v3: more simple fix. also fix one typo in pbus_size_mem Signed-off-by: Yinghai Lu <yinghai@kernel.org> Reviewed-by: Ram Pai <linuxram@us.ibm.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Kconfig.debug
menu "Kernel hacking"
source "lib/Kconfig.debug"
config DEBUG_STACKOVERFLOW
bool "Check for stack overflows"
depends on DEBUG_KERNEL
help
This option will cause messages to be printed if free stack space
drops below a certain limit.
config DEBUG_STACK_USAGE
bool "Stack utilization instrumentation"
depends on DEBUG_KERNEL
help
Enables the display of the minimum amount of free stack which each
task has ever had available in the sysrq-T and sysrq-P debug output.
This option will slow down process creation somewhat.
config DEBUG_PAGEALLOC
bool "Debug page memory allocations"
depends on DEBUG_KERNEL && BROKEN
help
Unmap pages from the kernel linear mapping after free_pages().
This results in a large slowdown, but helps to find certain types
of memory corruptions.
config FRAME_POINTER
bool "Compile the kernel with frame pointers"
help
If you say Y here the resulting kernel image will be slightly larger
and slower, but it will give very useful debugging information.
If you don't debug the kernel, you can say N, but we may not be able
to solve problems without frame pointers.
endmenu
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