Rockbox Technical Forums

Support and General Use => Hardware => Topic started by: 911boy on March 21, 2007, 01:34:35 AM

Title: Rockbox on sansa consumes more power
Post by: 911boy on March 21, 2007, 01:34:35 AM
I installed the latest build on my sansa e250.
seems the rockbox consumes more power than the original firmware.
Is it true? Has anyone else this same problem?

Do we have plan to improve it?

Thanks.
Title: Re: Rockbox on sansa consumes more power
Post by: Llorean on March 21, 2007, 01:52:17 AM
Yes, it's true. This happens on all PortalPlayer based devices. There's no "plan" to improve it because, although we'd really like to see it improved, it's not something one can develop a plan to tackle at this time. Optimizations will help, but until someone discovers what is causing the drain, it can't be fixed. A current suspicion is hardware that isn't properly being turned off when not in use.
Title: Re: Rockbox on sansa consumes more power
Post by: X86 on March 21, 2007, 02:23:35 AM
I that the problem is that the processor is running all the time,so it needs something to send it to temporary sleep,I think that,and I don't want anyone to get angry.
Title: Re: Rockbox on sansa consumes more power
Post by: LinusN on March 21, 2007, 03:17:16 AM
I that the problem is that the processor is running all the time,so it needs something to send it to temporary sleep,I think that,and I don't want anyone to get angry.
We have several problems on the PortalPlayer platforms. One of them is that the CPU isn't very fast, so we need to optimize the code more. Then there would be time for the CPU to go to sleep.

Also, there is another problem. Even when the CPU is completely idle, the player draws far too much power. We still don't know what causes this.
Title: Re: Rockbox on sansa consumes more power
Post by: X86 on March 21, 2007, 02:04:30 PM
I think is the backlit or the lcd display,the lcd display doesn't turn off even if you turn off backlit,it stays on all the time and it appears black,but if you see the lcd display with a little of light you might see that the display is working
Title: Re: Rockbox on sansa consumes more power
Post by: Llorean on March 21, 2007, 02:39:37 PM
Please, random guesses aren't going to solve this. As I said, it affects ALL PortalPlayer devices, and not other Rockbox devices, which strongly suggests it's something on the PortalPlayer chip, and not how Rockbox handles other things.

As well, the original Sansa Firmware does the same thing with the LCD.
Title: Re: Rockbox on sansa consumes more power
Post by: X86 on March 22, 2007, 01:53:55 PM
Llorean all the portalplayer chips have the same trouble,ohh... god,ok then is a common problem,ok and I'm going to analyze and think what's making that
Title: Re: Rockbox on sansa consumes more power
Post by: cvitullo on April 09, 2007, 04:20:16 PM
by the way, i think that when the original firmware turns off the screen it pauses everything but the audio, the play time is always behind when you press a button and the screen turns back on. as far as i know, rockbox doesn't do this. forgive me if i'm wrong, i'm just a noob.   :(
Title: Re: Rockbox on sansa consumes more power
Post by: Toni on April 10, 2007, 11:43:28 AM
I did some current measurements a few days ago with the Sansa:

Deactivating:
 - the lcd-device (when backlight off)
 - the ata-controller (if no read/write in progress)
Setting/resetting the correspondent bits in the DEV_EN register did the job.
In addition the usb device can be switched off (and on if needed).
I could reduce the current from 55mA to 41mA during mp3 playback.
The cpu frequency affects by ~1mA/4MHz.
Sleeping both cop and cpu has no effect. So a better solution might be to reduce the cpu/cop frequency if both cpu/cop are idling.

As a first step, frequency scaling should be enabled for the sansa.
Title: Re: Rockbox on sansa consumes more power
Post by: JdGordon on April 11, 2007, 01:10:43 AM
what current is the OF pulling during mp3 playback?
Title: Re: Rockbox on sansa consumes more power
Post by: linuxstb on April 11, 2007, 04:17:19 AM
Toni,

Did you measure the effects of ATA and LCD disabling individually?  I'm curious to know their relative contributions.
Title: Re: Rockbox on sansa consumes more power
Post by: Bagder on April 11, 2007, 06:22:08 AM
In addition the usb device can be switched off (and on if needed).

You know how? Done any measurements on the impact of disabling it?