On 11/6/05, M. Warner Losh <[EMAIL PROTECTED]> wrote: > In message: <[EMAIL PROTECTED]> > kylin <[EMAIL PROTECTED]> writes: > : /////////////// > : pci bridge dynamic resize > : ///////////// > : it seems that the device arch of freebsd is similar to what is revealed in > : window OS. i have read the pcie hotplug tps of windows longhorn ,it is said > : that with some hardware mechanisms the pci bridge driver can do global pci > : resource window reconfiguration.so good to the hotplugin pci device for it > : avoid prelocating resource for the device . > : i wonder ,if the mem /io/irq reconfiguration possible under freebsd .:) > : 1 > > Yes. Cardbus does it all the time. However, there's no pcie hot-plug > support yet, so the process for kicking off configuration of the new > device doesn't happen. > > Warner > sorry for my poor grammar ,i think i confused the public:) i will make myself clear with the words below about the PCI Multi-level Rebalance
PCI Multi-level Rebalance in Windows Longhorn Updated: November 25, 2003 The Microsoft(r) Windows(r) codename "Longhorn" operating system will include support for resource rebalancing at multiple levels across a PCI hierarchy. Windows Longhorn multi-level rebalancing supports systems that use multiple PCI-to-PCI bridge levels, including CardBus bridges, and also enhances support for hot plug technologies. However, multi-level rebalancing can expose problems in device drivers that do not handle Plug and Play I/O request packets (IRPs) correctly. Problem Scenarios Insufficient bridge resources appear when the platform BIOS cannot assign appropriate PCI-bridge resource windows during POST. Systems supporting hot-plug PCI devices are particularly problematic. When a PCI device can be hot-plugged behind a PCI bridge at run time, it is impossible for the BIOS to ascertain during POST how large a bridge resource window must be to accommodate a device. Additionally, a PCI bridge device might be hot plugged in certain situations—for example, in generic docking solutions that connect through CardBus adapters, or in the I/O expansion chassis often used in large server systems. Dynamic reconfiguration implies that a PCI bridge, whose resource windows are not being consumed by devices behind the bridge, might lose resources to another bridge that needs supplemental resources. Multi-level Rebalance Device Driver Requirements Windows device drivers must be carefully designed and thoroughly tested to properly support Windows Driver Model (WDM) stop semantics. The Stop request is an operational pause where the driver takes necessary steps to suspend an operation until the assignment of new resources is completed. Note: The rebalance process must remain transparent to applications and end users. End users might experience a temporary delay in a device's operation, but data must never be lost. Several events can trigger a resource rebalance request. For example, the system can fail to assign resources to a device behind a bridge whose resource windows are not opened wide enough to support the resource request. A device might also report that its resource requirements have changed at run time. Windows can also determine that a PCI bridge was configured to boot with a resource window that is larger than necessary, then Windows will reduce the size of the resource window and release associated resources. -- we who r about to die,salute u!
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