This patchset adds the SN Hotplug Driver to Linux. The patches are based on 2.6.12-rc1 (I haven't tried git yet ...) . The patches are [PATCH 1/6]: SN Hotplug Driver: SN IRQ fixes [PATCH 2/6]: SN Hotplug Driver: moving of header files [PATCH 3/6]: SN Hotplug Driver: pci_find_next_bus export [PATCH 4/6]: SN Hotplug Driver: new SN PROM version code [PATCH 5/6]: SN Hotplug Driver: SN Hotplug Driver code [PATCH 6/6]: SN Hotplug Driver: PREEMPT/pcibus_info fix The patches are incremental, however, the kernel will still compile after applying each patch. The first patch fixes the SN IRQ code such that cpu affinity and Hotplug can modify IRQ values. The sn_irq_info structures are now locked using a RCU lock mechanism to avoid lock contention in the lost interrupt WAR code. The second patch above moves header files out of the arch/ia64/sn directories and into include/asm-ia64/sn. These files were being included by other subsystems and should be under include/asm-ia64/sn. The third patch exports the pci_find_next_bus function to the rest of the kernel. The fourth patch above is a modification to the method in which the SN PROM information is examined in the kernel. The fifth patch is the SN Hotplug Driver and some additional required modifications. These modifications include changes to the SN io_init.c code for memory management, the inclusion of new SAL calls to enable and disable PCI slots, and a hotplug-style driver. The final patch fixes an issue with the PROM and a kernel running with CONFIG_PREEMPT enabled. When CONFIG_PREEMPT is enabled, the size of a spinlock_t changes -- resulting in the PROM writing to an incorrect location.