misc questions about the device&driver arch
M. Warner Losh
imp at bsdimp.com
Sat Nov 5 13:05:55 PST 2005
In message: <87ab37ab0511032030o134b9316j83295dd303e4e44b at mail.gmail.com>
kylin <fierykylin at gmail.com> 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 .:)
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.
: is bus_data_generation
: what idoes bus_data_generation for, is it the generation count for the
: device manager tree?
Anytime the device_t tree changes, this gets updated. It is used by
devinfo and friends.
: pci_write_config vs pci_write_config_method
: under the source code /dev/pci .there are functions name pci_write_config (
: pcivar.h) and pci_write_config_method(pci.c)
: they both call the parent method ,though the content is different ,but does
: that a liitle overlap whit each other?
pci_write_config is the user's interface. This gets translated into a
series of calls up the tree using pci_write_config_method to find the
right place in the tree to actually write to the configuration
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