misc questions about the device&driver arch

[John Baldwin]

On Thursday 10 November 2005 05:48 am, kylin wrote:
> Sir ,i am still puzzled by the windows and freebsd arch similar.
> 1
> the window TPS say that windwo allocate the resource window in default
> size of 1M or 2M,so there may be hole ,does that happen in freebsd 5
> or 6?

No.

> 2
> in my view i believe that freebsd us the "just enough "tactics,so
> the nexus level of resource view is ===continuous====with NO hole  in
> a boot up system,  IF hot remove do not happen .am i right?

Sorta.  We actually will use whatever the BIOS uses by default.  We only try 
to alloc resources if the BIOS doesn't, and I'm not sure how we handle a 
bridge running out of resources.  I think we might just fail the allocation.

> 3
> IF i do a PCI hotplug under a bridge, and the bridge 's MEM Window is
> full ,i have to do reballacne (including use the device_pause
> method:)), and if i can not declaim the resource from  other bridge
> because "nexus level of resource view is ===continuous====with NO hole
>  ", can i  extend the physical address space beyond the boot time
> locate range to PCI host bridge ?

Well, if you had device_pause() you would be able to shuffle resources from 
one bridge to another perhaps.  Preallocating bigger chunks as your first 
question suggested might be a lot simpler though not completely fool proof.

> On 11/6/05, John Baldwin <jhb at freebsd.org> wrote:
> > On Sunday 06 November 2005 06:14 am, kylin wrote:
> > > On 11/6/05, M. Warner Losh <imp at bsdimp.com> wrote:
> > > > 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
> > > > : .:) 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
> >
> > No, FreeBSD doesn't currently do what this decribes yet.  It would be
> > possible to do it by adding a new device_pause() method that drivers
> > would be required to implement while the resources were shuffled around
> > though and possibly a device_unpause() method so that they could update
> > their state if their resources were changed while the device was paused.
> >
> > --
> > John Baldwin <jhb at FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
> > "Power Users Use the Power to Serve" = http://www.FreeBSD.org
>
> --
> we who r about to die,salute u!

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org