On 6/6/2012 2:28 AM, Paul Walmsley wrote:
Hello Benoît
On Tue, 5 Jun 2012, Paul Walmsley wrote:
On Tue, 29 May 2012, Cousson, Benoit wrote:
So in fact, I'm wondering if a new flag is needed. We can potentially
apply that if idlemodes == (SIDLE_FORCE | SIDLE_NO).
We need to check which IP will have that to ensure that does not add
any side-effects.
I guess that means me :-)
I looked at a few TRMs. Based on that incomplete survey, the above
behavior would probably work for existing chips.
But it seems perverse to assume that it is generally safe to set an IP
block to force-idle while it's being used. That seems really dependent on
the IP block's integration.
Not really, because this behavior is implemented in the IP itself. The
point is the this IP is so dumb that force_idle = smart_idle. There is
not reason to delay the idle_ack since this IP does not do any internal
processing. That's probably why it was not implemented in the HW.
So in terms of a general fix, the flag approach seems safest to me in the
long run.
Well, for the long run we can expect the HW to be fixed, so since we do
have only one IP with that and we can detect that with the current
flags, I still do not think it is needed.
The other advantage of using a flag is that it indicates that this is a
hardware workaround; something that it would be nice to fix in future
chips.
Yeah, I'm still not convinced, but it is not a big deal either so it is
up to you.
Regards,
Benoit
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