Re: Threaded interrupts for synaptic touchscreen in HTC dream

[David Brownell <david-b-yBeKhBN/0LDR7s880joybQ@public.gmane.org>]

On Wednesday 22 July 2009, Thomas Gleixner wrote:
> 
> > I do think this should be set up by the driver - the platform/arch code
> > can't be 100% certain what model of servicing interrupts driver will
> > chose, nor the driver can know whether arch code set things up for
> > threaded or classic interrupt handling.
> > 
> > Since handle_level_oneshot_irq requires drivers to use threaded IRQ
> > model (in absence of thread interrupt will never be unmasked) it would
> > be better if we did set it up automatically, right there in
> > request_threaded_irq(). This would reduce maintenance issues between
> > platform and driver code.
> 
> No, it's the wrong way round. 
> 
> The platform code sets up the platform devices. So there is no real
> good reason that the platform code does not know about the details.

Except for the "development board" family of exceptions to
such rules ... or the "Processor-on-Card" model, where the
same platform/card gets used in a variety of different
chassis configurations, with different peripherals.

It may not be possible to know *which* configuration is
being used at board setup time.  However it most certainly
is known by the time a driver is configuring.