Re: [PATCH] OMAP2: gptimer min_delta_ns should be rounded up

[Aaro Koskinen <aaro.koskinen@nokia.com>]

Hello,

Woodruff, Richard wrote:
>> +             clockevent_delta2ns(1, &clockevent_gpt) + 1;
> 
> That value is still not correct.

[...]

>         clockevent_delta2ns(3, &clockevent_gpt);
> 
> min_delta_ns stops the frame work from trying to program an expiry time which may not be achievable due to timer costs.
> 
> A write to the timer when it has a 32KHz F-Clock can take ~3 32Khz clock cycles to complete.  Hence the cost of '3' not '1'.

I'm not sure if I see any problem. If the timer programming cost is 
bigger than min_delta_ns, the framework should adapt to it.

I guess you would want to make min_delta_ns bigger to avoid excessive 
scheduling/wakeups, but I think there is no any single "correct" value 
for every system/board.

A.