[ofw] RE: Release IBA resources in DISPATCH_LEVEL ?

[James Yang]

Hi Fab,

I think asynchronous mode with callback could be one of the solutions.
One of the examples is that I want to do it at power IRP which is at
IRQL_2.

Thanks,
James


-----Original Message-----
From: Fab Tillier [mailto:ftillier at windows.microsoft.com] 
Sent: Tuesday, June 10, 2008 3:35 PM
To: James Yang; ofw at lists.openfabrics.org
Subject: RE: Release IBA resources in DISPATCH_LEVEL ?

Hi James,

> Hi,
>
> My understanding with current WinOF1.2 code is that it can not allow
> drivers to call ibbus to release IBA
> resources(close/unregister/disconnect etc) at DISPATCH_LEVEL.

That is correct - no actions that perform any HW resource state change
can be done at DISPATCH_LEVEL, with the exception of allocating/freeing
address vectors.

> Will this
> restriction being remove in WinOF 1.2 or any later version? With this
> restriction it will cause a lot of troubles for devices boot over IB.

The HCA driver is what imposes this usage model on the stack, so you'd
have to effectively turn the whole call model upside down to fix this.
Pretty much a re-write of the whole stack.  Of course, you could support
the IBAL APIs on top of an async lower level, so IBAL kernel clients
wouldn't necessarily require changes, but the guts of IBAL and
everything below it would need to change significantly.

How would you envision this working?  Would you expect asynchronous
operations?  Would you want completions to be notified via callbacks or
IRP completions?

-Fab