misc questions about the device&driver arch

[william wallace]

On 6/4/06, M. Warner Losh <imp at bsdimp.com> wrote:
> In message: <87ab37ab0606040029u67edc35ende0b34e39e80bd37 at mail.gmail.com>
> : > > > Warner
> : Prior to removing a card from the system, two things must occur:
> :
> : The device's driver must cease accessing the card.
> :
> : The card must cease generation transaction and interrupts.
> :
> : How this is accomplished is OS-specific, but the following must take place:
> :
> : The OS must stop issuing new requests to the device's driver or must
> : instruct the driver to stop accepting new requests.
> :
> : The driver must terminate or complete all outstanding requests.
> :
> : The card must be disabled from generating interrupts or transactions.
> :
> : When the OS commands the driver to quiesce itself and its device, the
> : OS must not expect the device to remain in the system (in other words,
> : it could be removed and not replaced with a similar card).
> :
> : How to design and implement quiescing in freebsd?
>
> device_quiesce?  I have it in a p4 tree right now.  Specifically, it
> hooks up to the MOD_UNLOAD with a QUIESCE flag.  The driver's
> device_quiesce routine gets called, the driver sleeps there until it
> knows that it is good, then returns to the caller.  Then the driver's
> detach routine can be called.
>
> Warner
>
where can i get the p4 tree read ,sir

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