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Subject: running rockbox below 48MHz?

running rockbox below 48MHz?

From: Frederic Devernay <frederic.devernay_at_m4x.org>
Date: 2005-08-22

Hi,

When paused, or when playing CPU-savvy files (say, WAVE files), the
boost factor gets stuck at 0%. Wouldn't it be a good idea to use the
11MHz CPU speed in that case?

One idea would be to switch the low frequency between 11 and 48MHz:

- If the low frequency is 48MHz and the CPU frequency was 48MHz for more
than xxx millisecond, switch the low frequency to 11MHz.

- If the low frequency is 11MHz and the CPU was at 120MHz for more than
p% of the time during the last xxx milliseconds, switch the low
frequency to 48MHz. p is the solution to the following equation:
120*p + 11*(100-p) = 48*100
which makes approximately p=34%

That would decrease rockbox's battery usage a bit more (maybe not when
playing mp3s, but sometimes we're just browsing the file structure!).

Recording to WAV probably also requires little CPU, which means it could
switch to 11MHz and give more recording time on battery.

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Received on Mon Aug 22 19:43:45 2005


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