On 27.05.2011, at 12:33, Paul Mackerras wrote:

On Tue, May 17, 2011 at 12:17:50PM +0200, Alexander Graf wrote:

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=20
On 16.05.2011, at 07:58, Paul Mackerras wrote:
=20

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I do the check there because I was having problems where, if the =

HDEC

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goes negative before we do the partition switch, we would =

occasionally

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not get the HDEC interrupt at all until the next time HDEC went
negative, ~ 8.4 seconds later.

=20
Yikes - so HDEC is edge and doesn't even keep the interrupt line up?
That sounds like a serious hardware limitation. What if you only use
HDEC and it triggers while interrupts are off in a critical section?
Is the hardware really that broken?

=20
If HDEC expires when interrupts are off, the HDEC interrupt stays
pending until interrupts get re-enabled.  I'm not sure exactly what
the conditions are that cause an HDEC interrupt to get lost, but they
seem to involve at least a partition switch.

Please try to contact some of your hardware designers and figure out =
what exactly the conditions are. Maybe we don't need this hack.

Alex