[lkml]   [2007]   [May]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH 2.6.21-rt2] PowerPC: decrementer clockevent driver
>>> +     * We must write a positive value to the decrementer to clear
>>> + * the interrupt on the IBM 970 CPU series. In periodic mode,
>>> + * this happens when the decrementer gets reloaded later, but
>>> + * in one-shot mode, we have to do it here since an event
>>> handler
>>> + * may skip loading the new value...
>> Nothing special about 970 here -- on *every* PowerPC,
>> a decrementer exception exists as long as the high
>> bit of the decrementer equals 1. BookE is different
>> of course. Some other CPUs might deviate from the
>> architecture as well.
> Quoting "PowerPC Operating Environment Architecture":


> Otherwise, when the contents of DEC0 change, the exception effects of
> the Decrementer become consistent with the new contents of the
> Decrementer reasonably soon after the change.

And that is guaranteed on all PowerPC as far as I can see.
The main thing is that a decrementer exception won't go
away until the high bit becomes 0.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2007-05-17 21:53    [W:0.090 / U:6.936 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site