Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 15 Mar 2013 18:14:49 +0000 | From | Russell King - ARM Linux <> | Subject | Re: udelay function delays the wrong time interval in multiprocessor system, if ARCH_HAS_READ_CURRENT_TIMER is not defined and on current timer is used. |
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On Sat, Mar 16, 2013 at 12:08:54AM +0800, chpoph wrote: > If ARCH_HAS_READ_CURRENT_TIMER is not defined and on current timer is > used for udelay, then __loop_delay and __loop_const_udelay is used to > delay a specific time interval. but in delay-loop.S, loops_per_jiffy > (not per cpu data) is used to calculate the number of loops. in SMP > system, udelay delays the wrong time interval if two cpus running at > different frequency.
We don't support different CPUs running at different frequencies with the delay loop. Sorry.
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