iPod mini Battery Question

[Proxy]

Has the CPU clocking been worked on yet? I've searched around and I have no idea what the state of the iPod mini is at this point. Most information is outdated, looking through the recent changelogs didn't really help and I'm not sure if the rockbox hour meter is accurate on the iPod. Please help, thanks.

[scorche]

What specifically in regards to "CPU clocking" are you concerned about?

If you are asking "Does the battery runtime estimate produce an accurate estimate?", then the answer is no, it doesn't at the moment.

[Proxy]

I read mostly that its clocked at the maximum for stability reasons. Has this been optimized yet?

Thanks, I suspected as much.

[pixelma]

I think you mean the "frequency scaling" bug, where changing the CPU frequency (to save power) caused freezes on targets with a specific portalplayer chip (1st gen Mini was one of them). And some just disabled this frequency scaling which made Rockbox stable but the processor always ran at top frequency.

This has been fixed over half a year ago.

[Proxy]

It has? Does that mean rockbox now runs longer than the stock firmware?

[pixelma]

There are two parts of the story. Fixing this bug surely improved runtime compared to letting the processor run at top speed but worse runtime than the original firmware has (had) another reason - there are enough threads that explain it around here.

I'm not aware of someone testing runtime on a Mini under Rockbox compared to the original firmware after the fairly recent "device disabling" commit. On other devices with portalplayer chip this improved runtime a lot, so that it comes closer (or almost on par) with the stock firmware. You could be the one to try...

(I don't even have an Ipod and didn't care about it on my Sansa as I very seldom use it for so long that it runs out of battery.)

[Proxy]

There must be something very wrong with my settings, because rockbox drains it a lot faster than the stock firmware. Is there a reset for settings that would change all my power related settings to the default?

[Febs]

Yes.  Settings --> Manage settings --> Reset settings.

[Proxy]

I've tested this on an iPod with a 750mAh battery. It drains battery quite fast, I've used it for about three hours and the battery is at 64. I have no idea whats wrong, but its a second gen iPod with a CF card, and backlight off.

[Llorean]

How old is the battery. While a very roughly estimated 9 hours is short, it's not unreasonable for an old battery. As well, since you didn't do a full bench, we don't have any clue at what percentage / voltage it actually started at, nor what it would've actually ended at.

[Proxy]

Even if that was so, it should be much more improved because of the compact flash card inside.
The battery itself is not old, for it was recently purchased. I could try a benchmark, but is there an acurate meter for the iPod? I believe it was percieved that the rockbox meter was lacking? To do the benchmark, do I:
Put it at full volume?
Play a file at what format, what filesize, and and what bitrate?
Keep headphones on it?

Thanks.

[kadoban]

> Put it at full volume?
Probably doesn't matter much, just leave it at a reasonable volume.

> Play a file at what format, what filesize, and and what bitrate?
Might matter a little (but from what I understand, not much), just pick something general (mp3s or something) or have it loop through your collection.  I haven't seen a standard pick for this.

> Keep headphones on it?
Probably.

One thing you want to be careful of:  the backlight on all of the players that I know of is /very/ battery intensive.  You don't want to be pushing buttons all the time or else the backlight will keep coming on and could mess up your results.

If you're trying to compare the OF to rockbox, just be consistent between the two and you can't really go wrong.

And the most accurate meter for comparison is likely to just be: run it until it runs out of power, from a full charge.

[Chronon]

BatteryRuntime for info on running a battery runtime test.  I'm not sure if battery_bench will work properly on your CF mini or not.

[Proxy]

Thanks for the plugin. I'll post my results when I get them.

[soap]

BatteryRuntime for info on running a battery runtime test.  I'm not sure if battery_bench will work properly on your CF mini or not.

Personally, I think the Ipod Runtime page is also worth looking at, especially the most recent tests.  I believe it is the runtime page with the most pedantic attention to detail.

Two - a 750mah iPod mini battery is 50% larger than stock.  In my experience (take that with as large of a grain of salt as you wish) the larger the Li battery is versus stock the less reliable it is.