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FS#5686 - CPU Frequency scaling for iPod 3g

Attached to Project: Rockbox
Opened by Daniel Ankers (dan_a) - Thursday, 20 July 2006, 22:24 GMT+2
Task Type Patches
Category Operating System/Drivers
Status Closed
Assigned To No-one
Player Type iPod 3G
Severity Low
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Private No

Details

This patch implements CPU frequency scaling on the 3G iPod.
It uses a default frequency of 24MHz, a normal frequency of 30MHz and a maximum of 90MHz.
Although the PP5002 is rated to run at 90MHz, I believe that the normal iPod firmware does not run it at more than 75MHz, so we may wish to think about using that as the maximum.
This patch improves playback performance. It should also improve battery life when not playing.
(application/octet-stream)    3g-adjustable-cpu.diff (2.9 KiB) 
 firmware/system.c               |   33 +++++++++++++++++++++++++++++++++
 firmware/export/config-ipod3g.h |    2 +-
 firmware/export/system.h        |   10 ++++++++++
 3 files changed, 44 insertions(+), 1 deletion(-)

This task depends upon

Closed by  Dave Chapman (linuxstb)
Tuesday, 25 July 2006, 01:48 GMT+2
Reason for closing:  Accepted
Comment by Daniel Ankers (dan_a) - Monday, 24 July 2006, 00:33 GMT+2
Updated version:
Is not malformed
Leaves the maximum frequency at 75MHz

I have tested the effects of changing the CPU frequency in the debug menu while playing music, and the frequency scaling is definitely taking place.
(application/octet-stream)    3g-adjustable-cpu2.diff (1.6 KiB) 
 firmware/system.c               |   33 +++++++++++++++++++++++++++++++++
 firmware/export/config-ipod3g.h |    2 +-
 2 files changed, 34 insertions(+), 1 deletion(-)

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