Re: [PATCH 3/7] ARM i.MX6q: Add GPU, VPU, IPU, and OpenVG resets to System Reset Controller (SRC)

[Shawn Guo <shawn.guo-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>]

On Mon, Jan 21, 2013 at 11:47:12AM -0600, Matt Sealey wrote:
> > Yes, maybe the module reset part of the SRC should be implemented as a
> > proper device driver in drivers/reset. Then we could use the interrupt
> > functionality and WARN_ON(timeout), as you suggest.
> 
> That would be ideal. Maybe Shawn or Fabio can bug a hardware guy to
> shed some light on what a reasonable timeout might actually be for a
> module to cause such a warning. I think it should definitely cause
> one.. as I said, I was using 5 seconds, you used 1 second, I don't
> think a shorter delay would be unreasonable, but maybe it could take
> up to 10 seconds, or maybe I am wrong - maybe it is in fact impossible
> in hardware for a reset to "fail" at least visibly because the
> interrupt will always fire making the warning a never-traveled path.
> It is certainly not something that would be documented, so without a
> view of the RTL logic here, we wouldn't know.
> 
> Shawn, Fabio?
> 
Just talked to hardware people, the reset should finish in a few
clock cycles, so even 1 millisecond should be enough.

Shawn